Guide to the Secure Configuration of Fedora

with profile Common Profile for General-Purpose Fedora Systems
This profile contains items common to general-purpose Fedora installations.

This guide presents a catalog of security-relevant configuration settings for Fedora. It is a rendering of content structured in the eXtensible Configuration Checklist Description Format (XCCDF) in order to support security automation. The SCAP content is is available in the scap-security-guide package which is developed at https://www.open-scap.org/security-policies/scap-security-guide.

Providing system administrators with such guidance informs them how to securely configure systems under their control in a variety of network roles. Policy makers and baseline creators can use this catalog of settings, with its associated references to higher-level security control catalogs, in order to assist them in security baseline creation. This guide is a catalog, not a checklist, and satisfaction of every item is not likely to be possible or sensible in many operational scenarios. However, the XCCDF format enables granular selection and adjustment of settings, and their association with OVAL and OCIL content provides an automated checking capability. Transformations of this document, and its associated automated checking content, are capable of providing baselines that meet a diverse set of policy objectives. Some example XCCDF Profiles, which are selections of items that form checklists and can be used as baselines, are available with this guide. They can be processed, in an automated fashion, with tools that support the Security Content Automation Protocol (SCAP). The DISA STIG for Fedora, which provides required settings for US Department of Defense systems, is one example of a baseline created from this guidance.
Do not attempt to implement any of the settings in this guide without first testing them in a non-operational environment. The creators of this guidance assume no responsibility whatsoever for its use by other parties, and makes no guarantees, expressed or implied, about its quality, reliability, or any other characteristic.

Evaluation Characteristics

Target machinethinkpad
Benchmark URLssg-fedora-ds.xml
Benchmark IDxccdf_org.ssgproject.content_benchmark_FEDORA
Profile IDxccdf_org.ssgproject.content_profile_common
Started at2017-03-14T13:43:53
Finished at2017-03-14T13:49:23
Performed byjcerny

CPE Platforms

  • cpe:/o:fedoraproject:fedora:25
  • cpe:/o:fedoraproject:fedora:24
  • cpe:/o:fedoraproject:fedora:23

Addresses

  • IPv4  127.0.0.1
  • IPv4  10.40.3.41
  • IPv4  172.17.0.1
  • IPv4  192.168.122.1
  • IPv6  0:0:0:0:0:0:0:1
  • IPv6  2620:52:0:2802:5000:a46b:5715:bddd
  • IPv6  fe80:0:0:0:fe78:8fcb:8aee:26d7
  • IPv6  fe80:0:0:0:42:cbff:fef9:8c91
  • MAC  00:00:00:00:00:00
  • MAC  28:D2:44:DF:33:37
  • MAC  02:42:CB:F9:8C:91

Compliance and Scoring

The target system did not satisfy the conditions of 54 rules! Please review rule results and consider applying remediation.

Rule results

20 passed
54 failed
0 other

Severity of failed rules

0 other
34 low
18 medium
2 high

Score

Scoring systemScoreMaximumPercent
urn:xccdf:scoring:default57.513893100.000000
57.51%

Rule Overview

Group rules by:
TitleSeverityResult
Guide to the Secure Configuration of Fedora 54x fail
Remediation functions used by the SCAP Security Guide Project
Introduction
General Principles
Encrypt Transmitted Data Whenever Possible
Minimize Software to Minimize Vulnerability
Run Different Network Services on Separate Systems
Configure Security Tools to Improve System Robustness
Least Privilege
How to Use This Guide
Read Sections Completely and in Order
Test in Non-Production Environment
Root Shell Environment Assumed
Formatting Conventions
Reboot Required
System Settings 53x fail
Installing and Maintaining Software 4x fail
Updating Software 1x fail
gpgcheck Enabled In Main Dnf Configurationhigh
pass
gpgcheck Enabled For All Dnf Package Repositorieshigh
fail
Software Integrity Checking 3x fail
Verify Integrity with AIDE 1x fail
Install AIDEmedium
notselected
Build and Test AIDE Databasemedium
fail
Configure Periodic Execution of AIDEmedium
notselected
Verify Integrity with RPM 2x fail
Verify and Correct File Permissions with RPMlow
fail
Verify File Hashes with RPMlow
fail
Additional Security Software
Install Intrusion Detection Softwarehigh
notselected
Install Virus Scanning Softwarelow
notselected
GNOME Desktop Environment
Disable the GNOME3 Login User Listmedium
notselected
Disable the GNOME3 Login Restart and Shutdown Buttonshigh
notselected
Enable the GNOME3 Login Smartcard Authenticationmedium
notselected
Configure GNOME Screen Locking
Set GNOME3 Screensaver Inactivity Timeoutmedium
notselected
Enable GNOME3 Screensaver Idle Activationmedium
notselected
Enable GNOME3 Screensaver Lock After Idle Periodmedium
notselected
Implement Blank Screensaverlow
notselected
GNOME System Settings
Disable Ctrl-Alt-Del Reboot Key Sequence in GNOME3high
notselected
Disable User Administration in GNOME3high
notselected
Disable Power Settings in GNOME3medium
notselected
Disable Geolocation in GNOME3medium
notselected
GNOME Network Settings
Disable WIFI Network Connection Creation in GNOME3medium
notselected
Disable WIFI Network Notification in GNOME3medium
notselected
GNOME Remote Access Settings
Require Credential Prompting for Remote Access in GNOME3medium
notselected
Require Encryption for Remote Access in GNOME3medium
notselected
GNOME Media Settings
Disable GNOME3 Automountinglow
notselected
Disable All GNOME3 Thumbnailerslow
notselected
File Permissions and Masks 4x fail
Restrict Partition Mount Options
Add nodev Option to Non-Root Local Partitionslow
notselected
Add nodev Option to Removable Media Partitionslow
notselected
Add noexec Option to Removable Media Partitionslow
notselected
Add nosuid Option to Removable Media Partitionslow
notselected
Add nodev Option to /tmplow
notselected
Add noexec Option to /tmplow
notselected
Add nosuid Option to /tmplow
notselected
Add nodev Option to /dev/shmlow
notselected
Add noexec Option to /dev/shmlow
notselected
Add nosuid Option to /dev/shmlow
notselected
Bind Mount /var/tmp To /tmplow
notselected
Restrict Dynamic Mounting and Unmounting of Filesystems 1x fail
Disable Modprobe Loading of USB Storage Driverlow
notselected
Disable Kernel Support for USB via Bootloader Configurationlow
fail
Disable Booting from USB Devices in Boot Firmwarelow
notselected
Assign Password to Prevent Changes to Boot Firmware Configurationlow
notselected
Disable the Automounterlow
notselected
Disable Mounting of cramfslow
notselected
Disable Mounting of freevxfslow
notselected
Disable Mounting of jffs2low
notselected
Disable Mounting of hfslow
notselected
Disable Mounting of hfspluslow
notselected
Disable Mounting of squashfslow
notselected
Disable Mounting of udflow
notselected
Verify Permissions on Important Files and Directories 3x fail
Verify User Who Owns shadow Filemedium
notselected
Verify Group Who Owns shadow Filemedium
notselected
Verify Permissions on shadow Filemedium
notselected
Verify User Who Owns group Filemedium
notselected
Verify Group Who Owns group Filemedium
notselected
Verify Permissions on group Filemedium
notselected
Verify User Who Owns gshadow Filemedium
notselected
Verify Group Who Owns gshadow Filemedium
notselected
Verify Permissions on gshadow Filemedium
notselected
Verify User Who Owns passwd Filemedium
notselected
Verify Group Who Owns passwd Filemedium
notselected
Verify Permissions on passwd Filemedium
notselected
Verify File Permissions Within Some Important Directories 3x fail
Verify that Shared Library Files Have Restrictive Permissionsmedium
fail
Verify that Shared Library Files Have Root Ownershipmedium
fail
Verify that System Executables Have Restrictive Permissionsmedium
pass
Verify that System Executables Have Root Ownershipmedium
fail
Verify that All World-Writable Directories Have Sticky Bits Setlow
notselected
Ensure No World-Writable Files Existmedium
notselected
Ensure All SGID Executables Are Authorizedlow
notselected
Ensure All SUID Executables Are Authorizedlow
notselected
Ensure All Files Are Owned by a Usermedium
notselected
Ensure All Files Are Owned by a Groupmedium
notselected
Ensure All World-Writable Directories Are Owned by a System Accountlow
notselected
Restrict Programs from Dangerous Execution Patterns
Daemon Umask
Set Daemon Umasklow
notselected
Disable Core Dumps
Disable Core Dumps for All Userslow
notselected
Disable Core Dumps for SUID programslow
notselected
Enable ExecShield
Enable ExecShieldmedium
notselected
Enable Randomized Layout of Virtual Address Spacemedium
notselected
Enable Execute Disable (XD) or No Execute (NX) Support on x86 Systems
Install PAE Kernel on Supported 32-bit x86 Systemslow
notselected
Enable NX or XD Support in the BIOSlow
notselected
Restrict Access to Kernel Message Bufferlow
notselected
SELinux
Ensure SELinux Not Disabled in /etc/default/grubmedium
notselected
Ensure SELinux State is Enforcingmedium
notselected
Configure SELinux Policylow
notselected
Uninstall setroubleshoot Packagelow
notselected
Uninstall mcstrans Packagelow
notselected
Ensure No Daemons are Unconfined by SELinuxmedium
notselected
Ensure No Device Files are Unknown to SELinuxlow
notselected
Account and Access Control 6x fail
Protect Accounts by Restricting Password-Based Login 5x fail
Restrict Root Logins 1x fail
Direct root Logins Not Allowedmedium
fail
Serial Port Root Logins Restrictedlow
pass
Web Browser Use for Administrative Accounts Restrictedlow
notselected
System Accounts Do Not Run a Shell Upon Loginmedium
notselected
Only Root Has UID 0medium
pass
Root Path Is Vendor Defaultlow
notselected
Proper Storage and Existence of Password Hashes 1x fail
Log In to Accounts With Empty Password Impossiblehigh
fail
Password Hashes For Each Account Shadowedmedium
pass
All GIDs referenced in /etc/passwd Defined in /etc/grouplow
pass
netrc Files Do Not Existmedium
pass
Set Password Expiration Parameters 3x fail
Password Minimum Lengthmedium
fail
Password Minimum Agemedium
fail
Password Maximum Agemedium
fail
Protect Accounts by Configuring PAM 1x fail
Set Password Quality Requirements
Set Password Quality Requirements with pam_pwquality
Set Password Retry Prompts Permitted Per-Sessionlow
notselected
Set Password to Maximum of Three Consecutive Repeating Characterslow
notselected
Set Password to Maximum of Consecutive Repeating Characters from Same Character Classlow
notselected
Set Password Strength Minimum Digit Characterslow
notselected
Set Password Minimum Lengthlow
notselected
Set Password Strength Minimum Uppercase Characterslow
notselected
Set Password Strength Minimum Special Characterslow
notselected
Set Password Strength Minimum Lowercase Characterslow
notselected
Set Password Strength Minimum Different Characterslow
notselected
Set Password Strength Minimum Different Categorieslow
notselected
Set Lockouts for Failed Password Attempts
Set Deny For Failed Password Attemptsmedium
notselected
Set Lockout Time For Failed Password Attemptsmedium
notselected
Set Interval For Counting Failed Password Attemptsmedium
notselected
Limit Password Reusemedium
notselected
Set Password Hashing Algorithm
Set Password Hashing Algorithm in /etc/pam.d/system-authmedium
notselected
Set Password Hashing Algorithm in /etc/login.defsmedium
notselected
Set Password Hashing Algorithm in /etc/libuser.confmedium
notselected
Set Last Logon/Access Notificationlow
fail
Secure Session Configuration Files for Login Accounts
Ensure that No Dangerous Directories Exist in Root's Path
Ensure that Root's Path Does Not Include Relative Paths or Null Directorieslow
notselected
Ensure that Root's Path Does Not Include World or Group-Writable Directorieslow
pass
Ensure that Users Have Sensible Umask Values
Ensure the Default Bash Umask is Set Correctlylow
notselected
Ensure the Default C Shell Umask is Set Correctlylow
notselected
Ensure the Default Umask is Set Correctly in /etc/profilelow
notselected
Ensure that User Home Directories are not Group-Writable or World-Readablelow
notselected
Protect Physical Console Access
Set Boot Loader Password
Verify /boot/grub2/grub.cfg User Ownershipmedium
notselected
Verify /boot/grub2/grub.cfg Group Ownershipmedium
notselected
Verify /boot/grub2/grub.cfg Permissionsmedium
notselected
Set Boot Loader Passwordmedium
notselected
Set the UEFI Boot Loader Passwordmedium
notselected
Configure Screen Locking
Configure Console Screen Locking
Install the screen Packagemedium
notselected
Enable Smart Card Loginmedium
notselected
Require Authentication for Single User Modemedium
notselected
Disable debug-shell SystemD Servicemedium
notselected
Disable Ctrl-Alt-Del Reboot Activationhigh
notselected
Verify that Interactive Boot is Disabledmedium
notselected
Warning Banners for System Accesses
Enable GNOME3 Login Warning Bannermedium
notselected
Modify the System Login Bannermedium
notselected
Network Configuration and Firewalls 1x fail
Disable Unused Interfaces
Kernel Parameters Which Affect Networking
Network Parameters for Hosts Only
Disable Kernel Parameter for Sending ICMP Redirects by Defaultmedium
notselected
Disable Kernel Parameter for Sending ICMP Redirects for All Interfacesmedium
notselected
Disable Kernel Parameter for IP Forwardingmedium
notselected
Network Related Kernel Runtime Parameters for Hosts and Routers
Configure Kernel Parameter for Accepting Source-Routed Packets for All Interfacesmedium
notselected
Configure Kernel Parameter for Accepting ICMP Redirects for All Interfacesmedium
notselected
Configure Kernel Parameter for Accepting Secure Redirects for All Interfacesmedium
notselected
Configure Kernel Parameter to Log Martian Packetslow
notselected
Configure Kernel Parameter to Log Martian Packets By Defaultlow
notselected
Configure Kernel Parameter for Accepting Source-Routed Packets By Defaultmedium
notselected
Configure Kernel Parameter for Accepting ICMP Redirects By Defaultmedium
notselected
Configure Kernel Parameter for Accepting Secure Redirects By Defaultmedium
notselected
Configure Kernel Parameter to Ignore ICMP Broadcast Echo Requestsmedium
notselected
Configure Kernel Parameter to Ignore Bogus ICMP Error Responseslow
notselected
Configure Kernel Parameter to Use TCP Syncookiesmedium
notselected
Configure Kernel Parameter to Use Reverse Path Filtering for All Interfacesmedium
notselected
Configure Kernel Parameter to Use Reverse Path Filtering by Defaultmedium
notselected
Wireless Networking
Disable Wireless Through Software Configuration
Disable WiFi or Bluetooth in BIOSlow
notselected
Deactivate Wireless Network Interfaceslow
notselected
Disable Bluetooth Servicemedium
notselected
Disable Bluetooth Kernel Modulesmedium
notselected
IPv6
Disable Support for IPv6 Unless Needed
Disable IPv6 Networking Support Automatic Loadingmedium
notselected
Disable Interface Usage of IPv6low
notselected
Disable Support for RPC IPv6low
notselected
Configure IPv6 Settings if Necessary
Disable Automatic Configuration
Disable Accepting IPv6 Router Advertisementslow
notselected
Disable Accepting IPv6 Redirectsmedium
notselected
Limit Network-Transmitted Configuration if Using Static IPv6 Addresses
Manually Assign Global IPv6 Addresslow
notselected
Use Privacy Extensions for Addresslow
notselected
Manually Assign IPv6 Router Addresslow
notselected
firewalld 1x fail
Inspect and Activate Default firewalld Rules
Verify firewalld Enabledmedium
pass
Strengthen the Default Ruleset 1x fail
Set Default firewalld Zone for Incoming Packetsmedium
fail
Transport Layer Security Support
Uncommon Network Protocols
Disable DCCP Supportmedium
notselected
IPSec Support
Install libreswan Packagemedium
notselected
Verify Any Configured IPSec Tunnel Connectionsmedium
notselected
Disable Zeroconf Networkinglow
notselected
Ensure System is Not Acting as a Network Snifferlow
notselected
Configure Syslog
Ensure Proper Configuration of Log Files
Ensure Log Files Are Owned By Appropriate Usermedium
notselected
Ensure Log Files Are Owned By Appropriate Groupmedium
notselected
Ensure System Log Files Have Correct Permissionsmedium
notselected
Rsyslog Logs Sent To Remote Host
Ensure Logs Sent To Remote Hostlow
notselected
Configure rsyslogd to Accept Remote Messages If Acting as a Log Server
Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Serverlow
notselected
Enable rsyslog to Accept Messages via TCP, if Acting As Log Serverlow
notselected
Enable rsyslog to Accept Messages via UDP, if Acting As Log Serverlow
notselected
Ensure All Logs are Rotated by logrotate
Ensure Logrotate Runs Periodicallylow
notselected
Configure Logwatch on the Central Log Server
Configure Logwatch HostLimit Linelow
notselected
Configure Logwatch SplitHosts Linelow
notselected
Ensure rsyslog is Installedmedium
notselected
Enable rsyslog Servicemedium
notselected
Disable Logwatch on Clients if a Logserver Existslow
notselected
System Accounting with auditd 38x fail
Configure auditd Data Retention 7x fail
Configure auditd Number of Logs Retainedmedium
fail
Configure auditd Max Log File Sizemedium
fail
Configure auditd max_log_file_action Upon Reaching Maximum Log Sizemedium
fail
Configure auditd space_left Action on Low Disk Spacemedium
fail
Configure auditd admin_space_left Action on Low Disk Spacemedium
fail
Configure auditd mail_acct Action on Low Disk Spacemedium
fail
Configure auditd flush prioritylow
notselected
Configure auditd to use audispd's syslog pluginmedium
fail
Configure auditd Rules for Comprehensive Auditing 30x fail
Records Events that Modify Date and Time Information 5x fail
Record attempts to alter time through adjtimexlow
fail
Record attempts to alter time through settimeofdaylow
fail
Record Attempts to Alter Time Through stimelow
fail
Record Attempts to Alter Time Through clock_settimelow
fail
Record Attempts to Alter the localtime Filelow
fail
Record Events that Modify the System's Discretionary Access Controls 13x fail
Record Events that Modify the System's Discretionary Access Controls - chmodlow
fail
Record Events that Modify the System's Discretionary Access Controls - chownlow
fail
Record Events that Modify the System's Discretionary Access Controls - fchmodlow
fail
Record Events that Modify the System's Discretionary Access Controls - fchmodatlow
fail
Record Events that Modify the System's Discretionary Access Controls - fchownlow
fail
Record Events that Modify the System's Discretionary Access Controls - fchownatlow
fail
Record Events that Modify the System's Discretionary Access Controls - fremovexattrlow
fail
Record Events that Modify the System's Discretionary Access Controls - fsetxattrlow
fail
Record Events that Modify the System's Discretionary Access Controls - lchownlow
fail
Record Events that Modify the System's Discretionary Access Controls - lremovexattrlow
fail
Record Events that Modify the System's Discretionary Access Controls - lsetxattrlow
fail
Record Events that Modify the System's Discretionary Access Controls - removexattrlow
fail
Record Events that Modify the System's Discretionary Access Controls - setxattrlow
fail
Record Events that Modify User/Group Informationlow
fail
Record Events that Modify the System's Network Environmentlow
fail
System Audit Logs Must Have Mode 0640 or Less Permissivelow
notselected
System Audit Logs Must Be Owned By Rootlow
pass
Record Events that Modify the System's Mandatory Access Controlslow
fail
Record Attempts to Alter Logon and Logout Eventslow
fail
Record Attempts to Alter Process and Session Initiation Informationlow
fail
Ensure auditd Collects Unauthorized Access Attempts to Files (unsuccessful)low
fail
Ensure auditd Collects Information on the Use of Privileged Commandslow
fail
Ensure auditd Collects Information on Exporting to Media (successful)low
fail
Ensure auditd Collects File Deletion Events by Userlow
fail
Ensure auditd Collects System Administrator Actionslow
fail
Ensure auditd Collects Information on Kernel Module Loading and Unloadinglow
fail
Make the auditd Configuration Immutablelow
fail
Enable Auditing for Processes Which Start Prior to the Audit Daemonmedium
fail
Services 1x fail
Cron and At Daemons
Restrict at and cron to Authorized Users if Necessary
Enable cron Servicemedium
notselected
Disable anacron Servicelow
notselected
Disable At Service (atd)low
notselected
SSH Server
Configure OpenSSH Server if Necessary
SSH Access via Empty Passwords Disabledhigh
pass
SSH Idle Timeout Interval Usedlow
pass
SSH Client Alive Count Usedlow
pass
Network Time Protocol 1x fail
Enable the Chrony Daemonmedium
pass
Specify a Remote NTP Servermedium
fail
Specify Additional Remote NTP Serverslow
notselected
Audit Daemon
Enable the Audit Daemonmedium
pass
FTP Server
Disable vsftpd if Possible
Disable vsftpd Servicelow
notselected
Uninstall vsftpd Packagelow
notselected
Use vsftpd to Provide FTP Service if Necessary
Install vsftpd Packagelow
notselected
Use vsftpd to Provide FTP Service if Necessary
Restrict the Set of Users Allowed to Access FTP
Limit Users Allowed FTP Access if Necessary
Restrict Access to Anonymous Users if Possiblelow
notselected
Configure Firewalls to Protect the FTP Server
Enable Logging of All FTP Transactionslow
notselected
Create Warning Banners for All FTP Usersmedium
notselected
Disable FTP Uploads if Possiblelow
notselected
Place the FTP Home Directory on its Own Partitionlow
notselected
SNMP Server
Disable SNMP Server if Possible
Disable snmpd Servicelow
notselected
Uninstall net-snmp Packagelow
notselected
Configure SNMP Server if Necessary
Configure SNMP Service to Use Only SNMPv3 or Newer medium
notselected
Ensure Default Password Is Not Usedmedium
notselected
NFS and RPC
Disable All NFS Services if Possible
Disable Services Used Only by NFS
Disable Network File System Lock Service (nfslock)low
notselected
Disable Secure RPC Client Service (rpcgssd)low
notselected
Disable RPC ID Mapping Service (rpcidmapd)low
notselected
Disable netfs if Possible
Disable Network File Systems (netfs)low
notselected
Configure All Machines which Use NFS
Make Each Machine a Client or a Server, not Both
Configure NFS Services to Use Fixed Ports (NFSv3 and NFSv2)
Configure lockd to use static TCP portlow
notselected
Configure lockd to use static UDP portlow
notselected
Configure statd to use static portlow
notselected
Configure mountd to use static portlow
notselected
Configure NFS Clients
Disable NFS Server Daemons
Specify UID and GID for Anonymous NFS Connectionslow
notselected
Disable Network File System (nfs)low
notselected
Disable Secure RPC Server Service (rpcsvcgssd)low
notselected
Mount Remote Filesystems with Restrictive Options
Mount Remote Filesystems with nodevmedium
notselected
Mount Remote Filesystems with nosuidmedium
notselected
Configure NFS Servers
Configure the Exports File Restrictively
Use Access Lists to Enforce Authorization Restrictions
Export Filesystems Read-Only if Possible
Use Root-Squashing on All Exportslow
notselected
Restrict NFS Clients to Privileged Portslow
notselected
Ensure Insecure File Locking is Not Allowedmedium
notselected
X Window System
Disable X Windows
Disable X Windows Startup By Setting Default Targetlow
notselected
Remove the X Windows Package Grouplow
notselected

Result Details

gpgcheck Enabled In Main Dnf Configurationxccdf_org.ssgproject.content_rule_ensure_gpgcheck_globally_activated high

gpgcheck Enabled In Main Dnf Configuration

Rule IDxccdf_org.ssgproject.content_rule_ensure_gpgcheck_globally_activated
Result
pass
Time2017-03-14T13:43:53
Severityhigh
Identifiers and References

references:  SI-7, MA-1(b), 352, 663

Description

The gpgcheck option should be used to ensure checking of an RPM package's signature always occurs prior to its installation. To configure dnf to check package signatures before installing them, ensure the following line appears in /etc/dnf/dnf.conf in the [main] section:

gpgcheck=1

Rationale

Ensuring the validity of packages' cryptographic signatures prior to installation ensures the provenance of the software and protects against malicious tampering.

gpgcheck Enabled For All Dnf Package Repositoriesxccdf_org.ssgproject.content_rule_ensure_gpgcheck_never_disabled high

gpgcheck Enabled For All Dnf Package Repositories

Rule IDxccdf_org.ssgproject.content_rule_ensure_gpgcheck_never_disabled
Result
fail
Time2017-03-14T13:43:53
Severityhigh
Identifiers and References

references:  SI-7, MA-1(b), 352, 663

Description

To ensure signature checking is not disabled for any repos, remove any lines from files in /etc/yum.repos.d of the form:

gpgcheck=0

Rationale

Ensuring all packages' cryptographic signatures are valid prior to installation ensures the provenance of the software and protects against malicious tampering.

Install AIDExccdf_org.ssgproject.content_rule_package_aide_installed medium

Install AIDE

Rule IDxccdf_org.ssgproject.content_rule_package_aide_installed
Result
notselected
Time2017-03-14T13:43:53
Severitymedium
Identifiers and References

references:  CM-3(d), CM-3(e), CM-6(d), CM-6(3), SC-28, SI-7, 1069

Description

Install the AIDE package with the command:

$ sudo dnf install aide

Rationale

The AIDE package must be installed if it is to be available for integrity checking.

Build and Test AIDE Databasexccdf_org.ssgproject.content_rule_aide_build_database medium

Build and Test AIDE Database

Rule IDxccdf_org.ssgproject.content_rule_aide_build_database
Result
fail
Time2017-03-14T13:43:53
Severitymedium
Identifiers and References

references:  CM-3(d), CM-3(e), CM-6(d), CM-6(3), SC-28, SI-7

Description

Run the following command to generate a new database:

# /usr/sbin/aide --init
By default, the database will be written to the file /var/lib/aide/aide.db.new.gz. Storing the database, the configuration file /etc/aide.conf, and the binary /usr/sbin/aide (or hashes of these files), in a secure location (such as on read-only media) provides additional assurance about their integrity. The newly-generated database can be installed as follows:
# cp /var/lib/aide/aide.db.new.gz /var/lib/aide/aide.db.gz
To initiate a manual check, run the following command:
# /usr/sbin/aide --check
If this check produces any unexpected output, investigate.

Rationale

For AIDE to be effective, an initial database of "known-good" information about files must be captured and it should be able to be verified against the installed files.

Configure Periodic Execution of AIDExccdf_org.ssgproject.content_rule_aide_periodic_cron_checking medium

Configure Periodic Execution of AIDE

Rule IDxccdf_org.ssgproject.content_rule_aide_periodic_cron_checking
Result
notselected
Time2017-03-14T13:43:53
Severitymedium
Identifiers and References

references:  CM-3(d), CM-3(e), CM-6(d), CM-6(3), SC-28, SI-7, 374, 416, 1069, 1263, 1297, 1589

Description

To implement a daily execution of AIDE at 4:05am using cron, add the following line to /etc/crontab:

05 4 * * * root /usr/sbin/aide --check
AIDE can be executed periodically through other means; this is merely one example.

Rationale

By default, AIDE does not install itself for periodic execution. Periodically running AIDE is necessary to reveal unexpected changes in installed files.

Verify and Correct File Permissions with RPMxccdf_org.ssgproject.content_rule_rpm_verify_permissions low

Verify and Correct File Permissions with RPM

Rule IDxccdf_org.ssgproject.content_rule_rpm_verify_permissions
Result
fail
Time2017-03-14T13:45:34
Severitylow
Identifiers and References

references:  AC-6, CM-6(d), CM-6(3), 1493, 1494, 1495

Description

The RPM package management system can check file access permissions of installed software packages, including many that are important to system security. After locating a file with incorrect permissions, run the following command to determine which package owns it:

# rpm -qf FILENAME
Next, run the following command to reset its permissions to the correct values:
# rpm --setperms PACKAGENAME

Rationale

Permissions on system binaries and configuration files that are too generous could allow an unauthorized user to gain privileges that they should not have. The permissions set by the vendor should be maintained. Any deviations from this baseline should be investigated.

Remediation Ansible snippet:   (show)

Complexity:high
Disruption:medium
Strategy:restrict

- name: "Read list of files with incorrect permissions"
  shell: "rpm -Va | grep '^.M' | sed -r 's;^.*\\s+(.+);\\1;g'"
  register: files_with_incorrect_permissions
  failed_when: False
  changed_when: False

- name: "Correct file permissions with RPM"
  shell: "rpm --setperms $(rpm -qf '{{item}}')"
  with_items: "{{ files_with_incorrect_permissions.stdout_lines }}"
  when: files_with_incorrect_permissions.stdout_lines | length > 0

Verify File Hashes with RPMxccdf_org.ssgproject.content_rule_rpm_verify_hashes low

Verify File Hashes with RPM

Rule IDxccdf_org.ssgproject.content_rule_rpm_verify_hashes
Result
fail
Time2017-03-14T13:47:48
Severitylow
Identifiers and References

references:  CM-6(d), CM-6(3), SI-7, 1496

Description

The RPM package management system can check the hashes of installed software packages, including many that are important to system security. Run the following command to list which files on the system have hashes that differ from what is expected by the RPM database:

# rpm -Va | grep '^..5'
A "c" in the second column indicates that a file is a configuration file, which may appropriately be expected to change. If the file was not expected to change, investigate the cause of the change using audit logs or other means. The package can then be reinstalled to restore the file. Run the following command to determine which package owns the file:
# rpm -qf FILENAME
The package can be reinstalled from a dnf repository using the command:
dnf reinstall PACKAGENAME
Alternatively, the package can be reinstalled from trusted media using the command:
rpm -Uvh PACKAGENAME

Rationale

The hashes of important files like system executables should match the information given by the RPM database. Executables with erroneous hashes could be a sign of nefarious activity on the system.

Remediation Ansible snippet:   (show)

Complexity:high
Disruption:medium

- name: "Set fact: Package manager reinstall command (dnf)"
  set_fact:
    package_manager_reinstall_cmd: dnf reinstall -y
  when: ansible_distribution == "Fedora"

- name: "Set fact: Package manager reinstall command (yum)"
  set_fact:
    package_manager_reinstall_cmd: yum reinstall -y
  when: ansible_distribution == "RedHat"

- name: "Read files with incorrect hash"
  shell: "rpm -Va | grep -E '^..5.* /(bin|sbin|lib|lib64|usr)/' | sed -r 's;^.*\\s+(.+);\\1;g'"
  register: files_with_incorrect_hash
  changed_when: False
  when: package_manager_reinstall_cmd is defined

- name: "Reinstall packages of files with incorrect hash"
  shell: "{{package_manager_reinstall_cmd}} $(rpm -qf '{{item}}')"
  with_items: "{{ files_with_incorrect_hash.stdout_lines }}"
  when: package_manager_reinstall_cmd is defined and (files_with_incorrect_hash.stdout_lines | length > 0)
Install Intrusion Detection Softwarexccdf_org.ssgproject.content_rule_install_hids high

Install Intrusion Detection Software

Rule IDxccdf_org.ssgproject.content_rule_install_hids
Result
notselected
Time2017-03-14T13:47:48
Severityhigh
Identifiers and References

references:  SC-7, 1263

Description

The Red Hat platform includes a sophisticated auditing system and SELinux, which provide host-based intrusion detection capabilities.

Rationale

Host-based intrusion detection tools provide a system-level defense when an intruder gains access to a system or network.

Install Virus Scanning Softwarexccdf_org.ssgproject.content_rule_install_antivirus low

Install Virus Scanning Software

Rule IDxccdf_org.ssgproject.content_rule_install_antivirus
Result
notselected
Time2017-03-14T13:47:48
Severitylow
Identifiers and References

references:  SC-28, SI-3, 1239, 1668

Description

Install virus scanning software, which uses signatures to search for the presence of viruses on the filesystem. The McAfee VirusScan Enterprise for Linux virus scanning tool is provided for DoD systems. Ensure virus definition files are no older than 7 days, or their last release. Configure the virus scanning software to perform scans dynamically on all accessed files. If this is not possible, configure the system to scan all altered files on the system on a daily basis. If the system processes inbound SMTP mail, configure the virus scanner to scan all received mail.

Rationale

Virus scanning software can be used to detect if a system has been compromised by computer viruses, as well as to limit their spread to other systems.

Disable the GNOME3 Login User Listxccdf_org.ssgproject.content_rule_dconf_gnome_disable_user_list medium

Disable the GNOME3 Login User List

Rule IDxccdf_org.ssgproject.content_rule_dconf_gnome_disable_user_list
Result
notselected
Time2017-03-14T13:47:48
Severitymedium
Identifiers and References

references:  AC-23

Description

In the default graphical environment, users logging directly into the system are greeted with a login screen that displays all known users. This functionality should be disabled by setting disable-user-list to true.

To disable, add or edit disable-user-list to /etc/dconf/db/gdm.d/00-security-settings. For example:

[org/gnome/login-screen]
disable-user-list=true
Once the setting has been added, add a lock to /etc/dconf/db/gdm.d/locks/00-security-settings-lock to prevent user modification. For example:
/org/gnome/login-screen/disable-user-list
After the settings have been set, run dconf update.

Rationale

Leaving the user list enabled is a security risk since it allows anyone with physical access to the system to quickly enumerate known user accounts without logging in.

Disable the GNOME3 Login Restart and Shutdown Buttonsxccdf_org.ssgproject.content_rule_dconf_gnome_disable_restart_shutdown high

Disable the GNOME3 Login Restart and Shutdown Buttons

Rule IDxccdf_org.ssgproject.content_rule_dconf_gnome_disable_restart_shutdown
Result
notselected
Time2017-03-14T13:47:48
Severityhigh
Identifiers and References

references:  AC-6, 366

Description

In the default graphical environment, users logging directly into the system are greeted with a login screen that allows any user, known or unknown, the ability the ability to shutdown or restart the system. This functionality should be disabled by setting disable-restart-buttons to true.

To disable, add or edit disable-restart-buttons to /etc/dconf/db/gdm.d/00-security-settings. For example:

[org/gnome/login-screen]
disable-restart-buttons=true
Once the setting has been added, add a lock to /etc/dconf/db/gdm.d/locks/00-security-settings-lock to prevent user modification. For example:
/org/gnome/login-screen/disable-restart-buttons
After the settings have been set, run dconf update.

Rationale

A user who is at the console can reboot the system at the login screen. If restart or shutdown buttons are pressed at the login screen, this can create the risk of short-term loss of availability of systems due to reboot.

Enable the GNOME3 Login Smartcard Authenticationxccdf_org.ssgproject.content_rule_dconf_gnome_enable_smartcard_auth medium

Enable the GNOME3 Login Smartcard Authentication

Rule IDxccdf_org.ssgproject.content_rule_dconf_gnome_enable_smartcard_auth
Result
notselected
Time2017-03-14T13:47:48
Severitymedium
Identifiers and References

references:  765, 766, 767, 768, 771, 772, 884, Req-8.3

Description

In the default graphical environment, smart card authentication can be enabled on the login screen by setting enable-smartcard-authentication to true.

To enable, add or edit enable-smartcard-authentication to /etc/dconf/db/gdm.d/00-security-settings. For example:

[org/gnome/login-screen]
enable-smartcard-authentication=true
Once the setting has been added, add a lock to /etc/dconf/db/gdm.d/locks/00-security-settings-lock to prevent user modification. For example:
/org/gnome/login-screen/enable-smartcard-authentication
After the settings have been set, run dconf update.

Rationale

Smart card login provides two-factor authentication stronger than that provided by a username and password combination. Smart cards leverage PKI (public key infrastructure) in order to provide and verify credentials.

Set GNOME3 Screensaver Inactivity Timeoutxccdf_org.ssgproject.content_rule_dconf_gnome_screensaver_idle_delay medium

Set GNOME3 Screensaver Inactivity Timeout

Rule IDxccdf_org.ssgproject.content_rule_dconf_gnome_screensaver_idle_delay
Result
notselected
Time2017-03-14T13:47:48
Severitymedium
Identifiers and References

references:  AC-11(a), 57, Req-8.1.8

Description

The idle time-out value for inactivity in the GNOME3 desktop is configured via the idle-delay setting must be set under an appropriate configuration file(s) in the /etc/dconf/db/local.d directory and locked in /etc/dconf/db/local.d/locks directory to prevent user modification.
For example, to configure the system for a 15 minute delay, add the following to /etc/dconf/db/local.d/00-security-settings:

[org/gnome/desktop/session]
idle-delay=900
Once the setting has been added, add a lock to /etc/dconf/db/local.d/locks/00-security-settings-lock to prevent user modification. For example:
/org/gnome/desktop/session/idle-delay
After the settings have been set, run dconf update.

Rationale

A session time-out lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not logout because of the temporary nature of the absence. Rather than relying on the user to manually lock their operating system session prior to vacating the vicinity, GNOME3 can be configured to identify when a user's session has idled and take action to initiate a session lock.

Enable GNOME3 Screensaver Idle Activationxccdf_org.ssgproject.content_rule_dconf_gnome_screensaver_idle_activation_enabled medium

Enable GNOME3 Screensaver Idle Activation

Rule IDxccdf_org.ssgproject.content_rule_dconf_gnome_screensaver_idle_activation_enabled
Result
notselected
Time2017-03-14T13:47:48
Severitymedium
Identifiers and References

references:  AC-11(a), 57, Req-8.1.8

Description

To activate the screensaver in the GNOME3 desktop after a period of inactivity, add or set idle-activation-enabled to true in /etc/dconf/db/local.d/00-security-settings. For example:

[org/gnome/desktop/screensaver]
idle_activation_enabled=true
Once the setting has been added, add a lock to /etc/dconf/db/gdm.d/locks/00-security-settings-lock to prevent user modification. For example:
/org/gnome/desktop/screensaver/idle-activation-enabled
After the settings have been set, run dconf update.

Rationale

A session time-out lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not logout because of the temporary nature of the absence. Rather than relying on the user to manually lock their operating system session prior to vacating the vicinity, GNOME desktops can be configured to identify when a user's session has idled and take action to initiate the session lock. Enabling idle activation of the screensaver ensures the screensaver will be activated after the idle delay. Applications requiring continuous, real-time screen display (such as network management products) require the login session does not have administrator rights and the display station is located in a controlled-access area.

Enable GNOME3 Screensaver Lock After Idle Periodxccdf_org.ssgproject.content_rule_dconf_gnome_screensaver_lock_enabled medium

Enable GNOME3 Screensaver Lock After Idle Period

Rule IDxccdf_org.ssgproject.content_rule_dconf_gnome_screensaver_lock_enabled
Result
notselected
Time2017-03-14T13:47:48
Severitymedium
Identifiers and References

references:  AC-11(b), 56, Req-8.1.8

Description

To activate locking of the screensaver in the GNOME3 desktop when it is activated, add or set lock-enabled to true and lock-delay to 0 in /etc/dconf/db/local.d/00-security-settings. For example:

[org/gnome/desktop/screensaver]
lock-enabled=true
lock-delay=0
Once the settings have been added, add a lock to /etc/dconf/db/gdm.d/locks/00-security-settings-lock to prevent user modification. For example:
/org/gnome/desktop/screensaver/lock-enabled
/org/gnome/desktop/screensaver/lock-delay
After the settings have been set, run dconf update.

Rationale

A session lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not want to logout because of the temporary nature of the absense.

Implement Blank Screensaverxccdf_org.ssgproject.content_rule_dconf_gnome_screensaver_mode_blank low

Implement Blank Screensaver

Rule IDxccdf_org.ssgproject.content_rule_dconf_gnome_screensaver_mode_blank
Result
notselected
Time2017-03-14T13:47:48
Severitylow
Identifiers and References

references:  AC-11(b), 60, Req-8.1.8

Description

To set the screensaver mode in the GNOME3 desktop to a blank screen, add or set picture-uri to '' in /etc/dconf/db/local.d/00-security-settings. For example:

[org/gnome/desktop/screensaver]
picture-uri=''
Once the settings have been added, add a lock to /etc/dconf/db/gdm.d/locks/00-security-settings-lock to prevent user modification. For example:
/org/gnome/desktop/screensaver/picture-uri
After the settings have been set, run dconf update.

Rationale

Setting the screensaver mode to blank-only conceals the contents of the display from passersby.

Disable Ctrl-Alt-Del Reboot Key Sequence in GNOME3xccdf_org.ssgproject.content_rule_dconf_gnome_disable_ctrlaltdel_reboot high

Disable Ctrl-Alt-Del Reboot Key Sequence in GNOME3

Rule IDxccdf_org.ssgproject.content_rule_dconf_gnome_disable_ctrlaltdel_reboot
Result
notselected
Time2017-03-14T13:47:48
Severityhigh
Identifiers and References

references:  AC-6, 366

Description

By default, GNOME will reboot the system if the Ctrl-Alt-Del key sequence is pressed.
To configure the system to ignore the Ctrl-Alt-Del key sequence from the Graphical User Interface (GUI) instead of rebooting the system, add or set logout to '' in /etc/dconf/db/local.d/00-security-settings. For example:

[org/gnome/settings-daemon/plugins/media-keys]
logout=''
Once the settings have been added, add a lock to /etc/dconf/db/local.d/locks/00-security-settings-lock to prevent user modification. For example:
/org/gnome/settings-daemon/plugins/media-keys/logout
After the settings have been set, run dconf update.

Rationale

A locally logged-in user who presses Ctrl-Alt-Del, when at the console, can reboot the system. If accidentally pressed, as could happen in the case of mixed OS environment, this can create the risk of short-term loss of availability of systems due to unintentional reboot.

Disable User Administration in GNOME3xccdf_org.ssgproject.content_rule_dconf_gnome_disable_user_admin high

Disable User Administration in GNOME3

Rule IDxccdf_org.ssgproject.content_rule_dconf_gnome_disable_user_admin
Result
notselected
Time2017-03-14T13:47:48
Severityhigh
Identifiers and References
Description

By default, GNOME will allow all users to have some administratrion capability. This should be disabled so that non-administrative users are not making configuration changes. To configure the system to disable user administration capability in the Graphical User Interface (GUI), add or set user-administration-disabled to true in /etc/dconf/db/local.d/00-security-settings. For example:

[org/gnome/desktop/lockdown]
user-administration-disabled=true
Once the settings have been added, add a lock to /etc/dconf/db/local.d/locks/00-security-settings-lock to prevent user modification. For example:
/org/gnome/desktop/lockdown/user-administration-disabled
After the settings have been set, run dconf update.

Rationale

Allowing all users to have some administratrive capabilities to the system through the Graphical User Interface (GUI) when they would not have them otherwise could allow unintended configuration changes as well as a nefarious user the capability to make system changes such as adding new accounts, etc.

Disable Power Settings in GNOME3xccdf_org.ssgproject.content_rule_dconf_gnome_disable_power_settings medium

Disable Power Settings in GNOME3

Rule IDxccdf_org.ssgproject.content_rule_dconf_gnome_disable_power_settings
Result
notselected
Time2017-03-14T13:47:48
Severitymedium
Identifiers and References
Description

By default, GNOME enables a power profile designed for mobile devices with battery usage. While useful for mobile devices, this setting should be disabled for all other systems. To configure the system to disable the power setting, add or set active to false in /etc/dconf/db/local.d/00-security-settings. For example:

[org/gnome/settings-daemon/plugins/power]
active=false
Once the settings have been added, add a lock to /etc/dconf/db/local.d/locks/00-security-settings-lock to prevent user modification. For example:
/org/gnome/settings-daemon/plugins/power
After the settings have been set, run dconf update.

Rationale

Power settings should not be enabled on systems that are not mobile devices. Enabling power settings on non-mobile devices could have unintended processing consequences on standard systems.

Disable Geolocation in GNOME3xccdf_org.ssgproject.content_rule_dconf_gnome_disable_geolocation medium

Disable Geolocation in GNOME3

Rule IDxccdf_org.ssgproject.content_rule_dconf_gnome_disable_geolocation
Result
notselected
Time2017-03-14T13:47:48
Severitymedium
Identifiers and References
Description

GNOME allows the clock and applications to track and access location information. This setting should be disabled as applications should not track system location. To configure the system to disable location tracking, add or set enabled to false in /etc/dconf/db/local.d/00-security-settings. For example:

[org/gnome/system/location]
enabled=false
To configure the clock to disable location tracking, add or set geolocation to false in /etc/dconf/db/local.d/00-security-settings. For example:
[org/gnome/clocks]
geolocation=false
Once the settings have been added, add a lock to /etc/dconf/db/local.d/locks/00-security-settings-lock to prevent user modification. For example:
/org/gnome/system/location/enabled
/org/gnome/clocks/geolocation
After the settings have been set, run dconf update.

Rationale

Power settings should not be enabled on systems that are not mobile devices. Enabling power settings on non-mobile devices could have unintended processing consequences on standard systems.

Disable WIFI Network Connection Creation in GNOME3xccdf_org.ssgproject.content_rule_dconf_gnome_disable_wifi_create medium

Disable WIFI Network Connection Creation in GNOME3

Rule IDxccdf_org.ssgproject.content_rule_dconf_gnome_disable_wifi_create
Result
notselected
Time2017-03-14T13:47:48
Severitymedium
Identifiers and References
Description

GNOME allows users to create ad-hoc wireless connections through the NetworkManager applet. Wireless connections should be disabled by adding or setting disable-wifi-create to true in /etc/dconf/db/local.d/00-security-settings. For example:

[org/gnome/nm-applet]
disable-wifi-create=true
Once the settings have been added, add a lock to /etc/dconf/db/local.d/locks/00-security-settings-lock to prevent user modification. For example:
/org/gnome/nm-applet/disable-wifi-create
After the settings have been set, run dconf update.

Rationale

Wireless network connections should not be allowed to be configured by general users on a given system as it could open the system to backdoor attacks.

Disable WIFI Network Notification in GNOME3xccdf_org.ssgproject.content_rule_dconf_gnome_disable_wifi_notification medium

Disable WIFI Network Notification in GNOME3

Rule IDxccdf_org.ssgproject.content_rule_dconf_gnome_disable_wifi_notification
Result
notselected
Time2017-03-14T13:47:48
Severitymedium
Identifiers and References
Description

By default, GNOME disables WIFI notification. This should be permanently set so that users do not connect to a wireless network when the system finds one. While useful for mobile devices, this setting should be disabled for all other systems. To configure the system to disable the WIFI notication, add or set suppress-wireless-networks-available to true in /etc/dconf/db/local.d/00-security-settings. For example:

[org/gnome/nm-applet]
suppress-wireless-networks-available=true
Once the settings have been added, add a lock to /etc/dconf/db/local.d/locks/00-security-settings-lock to prevent user modification. For example:
/org/gnome/nm-applet/suppress-wireless-networks-available
After the settings have been set, run dconf update.

Rationale

Wireless network connections should not be allowed to be configured by general users on a given system as it could open the system to backdoor attacks.

Require Credential Prompting for Remote Access in GNOME3xccdf_org.ssgproject.content_rule_dconf_gnome_remote_access_credential_prompt medium

Require Credential Prompting for Remote Access in GNOME3

Rule IDxccdf_org.ssgproject.content_rule_dconf_gnome_remote_access_credential_prompt
Result
notselected
Time2017-03-14T13:47:48
Severitymedium
Identifiers and References
Description

By default, GNOME does not require credentials when using Vino for remote access. To configure the system to require remote credentials, add or set authentication-methods to ['vnc'] in /etc/dconf/db/local.d/00-security-settings. For example:

[org/gnome/Vino]
authentication-methods=['vnc']
Once the settings have been added, add a lock to /etc/dconf/db/local.d/locks/00-security-settings-lock to prevent user modification. For example:
/org/gnome/Vino/authentication-methods
After the settings have been set, run dconf update.

Rationale

Username and password prompting is required for remote access. Otherwise, non-authorized and nefarious users can access the system freely.

Require Encryption for Remote Access in GNOME3xccdf_org.ssgproject.content_rule_dconf_gnome_remote_access_encryption medium

Require Encryption for Remote Access in GNOME3

Rule IDxccdf_org.ssgproject.content_rule_dconf_gnome_remote_access_encryption
Result
notselected
Time2017-03-14T13:47:48
Severitymedium
Identifiers and References

references:  CM-2(1)(b), 366

Description

By default, GNOME requires encryption when using Vino for remote access. To prevent remote access encryption from being disabled, add or set require-encryption to true in /etc/dconf/db/local.d/00-security-settings. For example:

[org/gnome/Vino]
require-encryption=true
Once the settings have been added, add a lock to /etc/dconf/db/local.d/locks/00-security-settings-lock to prevent user modification. For example:
/org/gnome/Vino/require-encryption
After the settings have been set, run dconf update.

Rationale

Open X displays allow an attacker to capture keystrokes and to execute commands remotely.

Disable GNOME3 Automountingxccdf_org.ssgproject.content_rule_dconf_gnome_disable_automount low

Disable GNOME3 Automounting

Rule IDxccdf_org.ssgproject.content_rule_dconf_gnome_disable_automount
Result
notselected
Time2017-03-14T13:47:48
Severitylow
Identifiers and References

references:  AC-19(a), AC-19(d), AC-19(e)

Description

The system's default desktop environment, GNOME3, will mount devices and removable media (such as DVDs, CDs and USB flash drives) whenever they are inserted into the system. To disable automount and autorun within GNOME3, add or set automount to false, automount-open to false, and autorun-never to true in /etc/dconf/db/local.d/00-security-settings. For example:

[org/gnome/desktop/media-handling]
automount=false
automount-open=false
autorun-never=true
Once the settings have been added, add a lock to /etc/dconf/db/local.d/locks/00-security-settings-lock to prevent user modification. For example:
/org/gnome/desktop/media-handling/automount
/org/gnome/desktop/media-handling/auto-open
/org/gnome/desktop/media-handling/autorun-never
After the settings have been set, run dconf update.

Rationale

Disabling automatic mounting in GNOME3 can prevent the introduction of malware via removable media. It will, however, also prevent desktop users from legitimate use of removable media.

Disable All GNOME3 Thumbnailersxccdf_org.ssgproject.content_rule_dconf_gnome_disable_thumbnailers low

Disable All GNOME3 Thumbnailers

Rule IDxccdf_org.ssgproject.content_rule_dconf_gnome_disable_thumbnailers
Result
notselected
Time2017-03-14T13:47:48
Severitylow
Identifiers and References

references:  CM-7

Description

The system's default desktop environment, GNOME3, uses a number of different thumbnailer programs to generate thumbnails for any new or modified content in an opened folder. To disable the execution of these thumbnail applications, add or set disable-all to true in /etc/dconf/db/local.d/00-security-settings. For example:

[org/gnome/desktop/thumbnailers]
disable-all=true
Once the settings have been added, add a lock to /etc/dconf/db/local.d/locks/00-security-settings-lock to prevent user modification. For example:
/org/gnome/desktop/thumbnailers/disable-all
After the settings have been set, run dconf update. This effectively prevents an attacker from gaining access to a system through a flaw in GNOME3's Nautilus thumbnail creators.

Rationale

An attacker with knowledge of a flaw in a GNOME3 thumbnailer application could craft a malicious file to exploit this flaw. Assuming the attacker could place the malicious file on the local filesystem (via a web upload for example) and assuming a user browses the same location using Nautilus, the malicious file would exploit the thumbnailer with the potential for malicious code execution. It is best to disable these thumbnailer applications unless they are explicitly required.

Add nodev Option to Non-Root Local Partitionsxccdf_org.ssgproject.content_rule_mount_option_nodev_nonroot_local_partitions low

Add nodev Option to Non-Root Local Partitions

Rule IDxccdf_org.ssgproject.content_rule_mount_option_nodev_nonroot_local_partitions
Result
notselected
Time2017-03-14T13:47:48
Severitylow
Identifiers and References

references:  CM-7

Description

The nodev mount option prevents files from being interpreted as character or block devices. Legitimate character and block devices should exist only in the /dev directory on the root partition or within chroot jails built for system services. Add the nodev option to the fourth column of /etc/fstab for the line which controls mounting of any non-root local partitions.

Rationale

The nodev mount option prevents files from being interpreted as character or block devices. The only legitimate location for device files is the /dev directory located on the root partition. The only exception to this is chroot jails, for which it is not advised to set nodev on these filesystems.

Add nodev Option to Removable Media Partitionsxccdf_org.ssgproject.content_rule_mount_option_nodev_removable_partitions low

Add nodev Option to Removable Media Partitions

Rule IDxccdf_org.ssgproject.content_rule_mount_option_nodev_removable_partitions
Result
notselected
Time2017-03-14T13:47:48
Severitylow
Identifiers and References

references:  AC-19(a), AC-19(d), AC-19(e), CM-7, MP-2

Description

The nodev mount option prevents files from being interpreted as character or block devices. Legitimate character and block devices should exist only in the /dev directory on the root partition or within chroot jails built for system services. Add the nodev option to the fourth column of /etc/fstab for the line which controls mounting of any removable media partitions.

Rationale

The only legitimate location for device files is the /dev directory located on the root partition. An exception to this is chroot jails, and it is not advised to set nodev on partitions which contain their root filesystems.

Add noexec Option to Removable Media Partitionsxccdf_org.ssgproject.content_rule_mount_option_noexec_removable_partitions low

Add noexec Option to Removable Media Partitions

Rule IDxccdf_org.ssgproject.content_rule_mount_option_noexec_removable_partitions
Result
notselected
Time2017-03-14T13:47:48
Severitylow
Identifiers and References

references:  AC-19(a), AC-19(d), AC-19(e), CM-7, MP-2, 87

Description

The noexec mount option prevents the direct execution of binaries on the mounted filesystem. Preventing the direct execution of binaries from removable media (such as a USB key) provides a defense against malicious software that may be present on such untrusted media. Add the noexec option to the fourth column of /etc/fstab for the line which controls mounting of any removable media partitions.

Rationale

Allowing users to execute binaries from removable media such as USB keys exposes the system to potential compromise.

Add nosuid Option to Removable Media Partitionsxccdf_org.ssgproject.content_rule_mount_option_nosuid_removable_partitions low

Add nosuid Option to Removable Media Partitions

Rule IDxccdf_org.ssgproject.content_rule_mount_option_nosuid_removable_partitions
Result
notselected
Time2017-03-14T13:47:48
Severitylow
Identifiers and References

references:  AC-19(a), AC-19(d), AC-19(e), CM-7, MP-2

Description

The nosuid mount option prevents set-user-identifier (SUID) and set-group-identifier (SGID) permissions from taking effect. These permissions allow users to execute binaries with the same permissions as the owner and group of the file respectively. Users should not be allowed to introduce SUID and SGID files into the system via partitions mounted from removeable media. Add the nosuid option to the fourth column of /etc/fstab for the line which controls mounting of any removable media partitions.

Rationale

The presence of SUID and SGID executables should be tightly controlled. Allowing users to introduce SUID or SGID binaries from partitions mounted off of removable media would allow them to introduce their own highly-privileged programs.

Add nodev Option to /tmpxccdf_org.ssgproject.content_rule_mount_option_tmp_nodev low

Add nodev Option to /tmp

Rule IDxccdf_org.ssgproject.content_rule_mount_option_tmp_nodev
Result
notselected
Time2017-03-14T13:47:48
Severitylow
Identifiers and References

references:  CM-7, MP-2

Description

The nodev mount option can be used to prevent device files from being created in /tmp. Legitimate character and block devices should not exist within temporary directories like /tmp. Add the nodev option to the fourth column of /etc/fstab for the line which controls mounting of /tmp.

Rationale

The only legitimate location for device files is the /dev directory located on the root partition. The only exception to this is chroot jails.

Add noexec Option to /tmpxccdf_org.ssgproject.content_rule_mount_option_tmp_noexec low

Add noexec Option to /tmp

Rule IDxccdf_org.ssgproject.content_rule_mount_option_tmp_noexec
Result
notselected
Time2017-03-14T13:47:48
Severitylow
Identifiers and References

references:  CM-7, MP-2

Description

The noexec mount option can be used to prevent binaries from being executed out of /tmp. Add the noexec option to the fourth column of /etc/fstab for the line which controls mounting of /tmp.

Rationale

Allowing users to execute binaries from world-writable directories such as /tmp should never be necessary in normal operation and can expose the system to potential compromise.

Add nosuid Option to /tmpxccdf_org.ssgproject.content_rule_mount_option_tmp_nosuid low

Add nosuid Option to /tmp

Rule IDxccdf_org.ssgproject.content_rule_mount_option_tmp_nosuid
Result
notselected
Time2017-03-14T13:47:48
Severitylow
Identifiers and References

references:  CM-7, MP-2

Description

The nosuid mount option can be used to prevent execution of setuid programs in /tmp. The SUID and SGID permissions should not be required in these world-writable directories. Add the nosuid option to the fourth column of /etc/fstab for the line which controls mounting of /tmp.

Rationale

The presence of SUID and SGID executables should be tightly controlled. Users should not be able to execute SUID or SGID binaries from temporary storage partitions.

Add nodev Option to /dev/shmxccdf_org.ssgproject.content_rule_mount_option_dev_shm_nodev low

Add nodev Option to /dev/shm

Rule IDxccdf_org.ssgproject.content_rule_mount_option_dev_shm_nodev
Result
notselected
Time2017-03-14T13:47:48
Severitylow
Identifiers and References

references:  CM-7, MP-2

Description

The nodev mount option can be used to prevent creation of device files in /dev/shm. Legitimate character and block devices should not exist within temporary directories like /dev/shm. Add the nodev option to the fourth column of /etc/fstab for the line which controls mounting of /dev/shm.

Rationale

The only legitimate location for device files is the /dev directory located on the root partition. The only exception to this is chroot jails.

Add noexec Option to /dev/shmxccdf_org.ssgproject.content_rule_mount_option_dev_shm_noexec low

Add noexec Option to /dev/shm

Rule IDxccdf_org.ssgproject.content_rule_mount_option_dev_shm_noexec
Result
notselected
Time2017-03-14T13:47:48
Severitylow
Identifiers and References

references:  CM-7, MP-2

Description

The noexec mount option can be used to prevent binaries from being executed out of /dev/shm. It can be dangerous to allow the execution of binaries from world-writable temporary storage directories such as /dev/shm. Add the noexec option to the fourth column of /etc/fstab for the line which controls mounting of /dev/shm.

Rationale

Allowing users to execute binaries from world-writable directories such as /dev/shm can expose the system to potential compromise.

Add nosuid Option to /dev/shmxccdf_org.ssgproject.content_rule_mount_option_dev_shm_nosuid low

Add nosuid Option to /dev/shm

Rule IDxccdf_org.ssgproject.content_rule_mount_option_dev_shm_nosuid
Result
notselected
Time2017-03-14T13:47:48
Severitylow
Identifiers and References

references:  CM-7, MP-2

Description

The nosuid mount option can be used to prevent execution of setuid programs in /dev/shm. The SUID and SGID permissions should not be required in these world-writable directories. Add the nosuid option to the fourth column of /etc/fstab for the line which controls mounting of /dev/shm.

Rationale

The presence of SUID and SGID executables should be tightly controlled. Users should not be able to execute SUID or SGID binaries from temporary storage partitions.

Bind Mount /var/tmp To /tmpxccdf_org.ssgproject.content_rule_mount_option_var_tmp_bind low

Bind Mount /var/tmp To /tmp

Rule IDxccdf_org.ssgproject.content_rule_mount_option_var_tmp_bind
Result
notselected
Time2017-03-14T13:47:48
Severitylow
Identifiers and References

references:  CM-7

Description

The /var/tmp directory is a world-writable directory. Bind-mount it to /tmp in order to consolidate temporary storage into one location protected by the same techniques as /tmp. To do so, edit /etc/fstab and add the following line:

/tmp     /var/tmp     none     rw,nodev,noexec,nosuid,bind     0 0
See the mount(8) man page for further explanation of bind mounting.

Rationale

Having multiple locations for temporary storage is not required. Unless absolutely necessary to meet requirements, the storage location /var/tmp should be bind mounted to /tmp and thus share the same protections.

Disable Modprobe Loading of USB Storage Driverxccdf_org.ssgproject.content_rule_kernel_module_usb-storage_disabled low

Disable Modprobe Loading of USB Storage Driver

Rule IDxccdf_org.ssgproject.content_rule_kernel_module_usb-storage_disabled
Result
notselected
Time2017-03-14T13:47:48
Severitylow
Identifiers and References

references:  AC-19(a), AC-19(d), AC-19(e), 1250, 85

Description

To prevent USB storage devices from being used, configure the kernel module loading system to prevent automatic loading of the USB storage driver. To configure the system to prevent the usb-storage kernel module from being loaded, add the following line to a file in the directory /etc/modprobe.d:

install usb-storage /bin/true
This will prevent the modprobe program from loading the usb-storage module, but will not prevent an administrator (or another program) from using the insmod program to load the module manually.

Rationale

USB storage devices such as thumb drives can be used to introduce malicious software.

Disable Kernel Support for USB via Bootloader Configurationxccdf_org.ssgproject.content_rule_bootloader_nousb_argument low

Disable Kernel Support for USB via Bootloader Configuration

Rule IDxccdf_org.ssgproject.content_rule_bootloader_nousb_argument
Result
fail
Time2017-03-14T13:47:48
Severitylow
Identifiers and References

references:  AC-19(a), AC-19(d), AC-19(e), 1250

Description

All USB support can be disabled by adding the nousb argument to the kernel's boot loader configuration. To do so, append "nousb" to the kernel line in /etc/default/grub as shown:

kernel /vmlinuz-VERSION ro vga=ext root=/dev/VolGroup00/LogVol00 rhgb quiet nousb
WARNING: Disabling all kernel support for USB will cause problems for systems with USB-based keyboards, mice, or printers. This configuration is infeasible for systems which require USB devices, which is common.

Rationale

Disabling the USB subsystem within the Linux kernel at system boot will protect against potentially malicious USB devices, although it is only practical in specialized systems.

Remediation Shell script:   (show)

Complexity:high
Disruption:medium
Strategy:restrict

# Correct the form of default kernel command line in /etc/default/grub
if ! grep -q ^GRUB_CMDLINE_LINUX=\".*nousb.*\" /etc/default/grub;
then
  # Edit configuration setting
  # Append 'nousb' argument to /etc/default/grub (if not present yet)
  sed -i "s/\(GRUB_CMDLINE_LINUX=\)\"\(.*\)\"/\1\"\2 nousb\"/" /etc/default/grub
  # Edit runtime setting
  # Correct the form of kernel command line for each installed kernel in the bootloader
  /sbin/grubby --update-kernel=ALL --args="nousb"
fi
Disable Booting from USB Devices in Boot Firmwarexccdf_org.ssgproject.content_rule_bios_disable_usb_boot low

Disable Booting from USB Devices in Boot Firmware

Rule IDxccdf_org.ssgproject.content_rule_bios_disable_usb_boot
Result
notselected
Time2017-03-14T13:47:48
Severitylow
Identifiers and References

references:  AC-19(a), AC-19(d), AC-19(e), 1250

Description

Configure the system boot firmware (historically called BIOS on PC systems) to disallow booting from USB drives.

Rationale

Booting a system from a USB device would allow an attacker to circumvent any security measures provided by the operating system. Attackers could mount partitions and modify the configuration of the OS.

Assign Password to Prevent Changes to Boot Firmware Configurationxccdf_org.ssgproject.content_rule_bios_assign_password low

Assign Password to Prevent Changes to Boot Firmware Configuration

Rule IDxccdf_org.ssgproject.content_rule_bios_assign_password
Result
notselected
Time2017-03-14T13:47:48
Severitylow
Identifiers and References
Description

Assign a password to the system boot firmware (historically called BIOS on PC systems) to require a password for any configuration changes.

Rationale

Assigning a password to the system boot firmware prevents anyone with physical access from configuring the system to boot from local media and circumvent the operating system's access controls. For systems in physically secure locations, such as a data center or Sensitive Compartmented Information Facility (SCIF), this risk must be weighed against the risk of administrative personnel being unable to conduct recovery operations in a timely fashion.

Disable the Automounterxccdf_org.ssgproject.content_rule_service_autofs_disabled low

Disable the Automounter

Rule IDxccdf_org.ssgproject.content_rule_service_autofs_disabled
Result
notselected
Time2017-03-14T13:47:48
Severitylow
Identifiers and References

references:  AC-19(a), AC-19(d), AC-19(e), 1250, 85

Description

The autofs daemon mounts and unmounts filesystems, such as user home directories shared via NFS, on demand. In addition, autofs can be used to handle removable media, and the default configuration provides the cdrom device as /misc/cd. However, this method of providing access to removable media is not common, so autofs can almost always be disabled if NFS is not in use. Even if NFS is required, it may be possible to configure filesystem mounts statically by editing /etc/fstab rather than relying on the automounter.

The autofs service can be disabled with the following command:

$ sudo systemctl disable autofs.service

Rationale

Disabling the automounter permits the administrator to statically control filesystem mounting through /etc/fstab.

Disable Mounting of cramfsxccdf_org.ssgproject.content_rule_kernel_module_cramfs_disabled low

Disable Mounting of cramfs

Rule IDxccdf_org.ssgproject.content_rule_kernel_module_cramfs_disabled
Result
notselected
Time2017-03-14T13:47:48
Severitylow
Identifiers and References

references:  CM-7

Description

To configure the system to prevent the cramfs kernel module from being loaded, add the following line to a file in the directory /etc/modprobe.d:

install cramfs /bin/true
This effectively prevents usage of this uncommon filesystem.

Rationale

Linux kernel modules which implement filesystems that are not needed by the local system should be disabled.

Disable Mounting of freevxfsxccdf_org.ssgproject.content_rule_kernel_module_freevxfs_disabled low

Disable Mounting of freevxfs

Rule IDxccdf_org.ssgproject.content_rule_kernel_module_freevxfs_disabled
Result
notselected
Time2017-03-14T13:47:48
Severitylow
Identifiers and References

references:  CM-7

Description

To configure the system to prevent the freevxfs kernel module from being loaded, add the following line to a file in the directory /etc/modprobe.d:

install freevxfs /bin/true
This effectively prevents usage of this uncommon filesystem.

Rationale

Linux kernel modules which implement filesystems that are not needed by the local system should be disabled.

Disable Mounting of jffs2xccdf_org.ssgproject.content_rule_kernel_module_jffs2_disabled low

Disable Mounting of jffs2

Rule IDxccdf_org.ssgproject.content_rule_kernel_module_jffs2_disabled
Result
notselected
Time2017-03-14T13:47:48
Severitylow
Identifiers and References

references:  CM-7

Description

To configure the system to prevent the jffs2 kernel module from being loaded, add the following line to a file in the directory /etc/modprobe.d:

install jffs2 /bin/true
This effectively prevents usage of this uncommon filesystem.

Rationale

Linux kernel modules which implement filesystems that are not needed by the local system should be disabled.

Disable Mounting of hfsxccdf_org.ssgproject.content_rule_kernel_module_hfs_disabled low

Disable Mounting of hfs

Rule IDxccdf_org.ssgproject.content_rule_kernel_module_hfs_disabled
Result
notselected
Time2017-03-14T13:47:48
Severitylow
Identifiers and References

references:  CM-7

Description

To configure the system to prevent the hfs kernel module from being loaded, add the following line to a file in the directory /etc/modprobe.d:

install hfs /bin/true
This effectively prevents usage of this uncommon filesystem.

Rationale

Linux kernel modules which implement filesystems that are not needed by the local system should be disabled.

Disable Mounting of hfsplusxccdf_org.ssgproject.content_rule_kernel_module_hfsplus_disabled low

Disable Mounting of hfsplus

Rule IDxccdf_org.ssgproject.content_rule_kernel_module_hfsplus_disabled
Result
notselected
Time2017-03-14T13:47:48
Severitylow
Identifiers and References

references:  CM-7

Description

To configure the system to prevent the hfsplus kernel module from being loaded, add the following line to a file in the directory /etc/modprobe.d:

install hfsplus /bin/true
This effectively prevents usage of this uncommon filesystem.

Rationale

Linux kernel modules which implement filesystems that are not needed by the local system should be disabled.

Disable Mounting of squashfsxccdf_org.ssgproject.content_rule_kernel_module_squashfs_disabled low

Disable Mounting of squashfs

Rule IDxccdf_org.ssgproject.content_rule_kernel_module_squashfs_disabled
Result
notselected
Time2017-03-14T13:47:48
Severitylow
Identifiers and References

references:  CM-7

Description

To configure the system to prevent the squashfs kernel module from being loaded, add the following line to a file in the directory /etc/modprobe.d:

install squashfs /bin/true
This effectively prevents usage of this uncommon filesystem.

Rationale

Linux kernel modules which implement filesystems that are not needed by the local system should be disabled.

Disable Mounting of udfxccdf_org.ssgproject.content_rule_kernel_module_udf_disabled low

Disable Mounting of udf

Rule IDxccdf_org.ssgproject.content_rule_kernel_module_udf_disabled
Result
notselected
Time2017-03-14T13:47:48
Severitylow
Identifiers and References

references:  CM-7

Description

To configure the system to prevent the udf kernel module from being loaded, add the following line to a file in the directory /etc/modprobe.d:

install udf /bin/true
This effectively prevents usage of this uncommon filesystem.

Rationale

Linux kernel modules which implement filesystems that are not needed by the local system should be disabled.

Verify User Who Owns shadow Filexccdf_org.ssgproject.content_rule_userowner_shadow_file medium

Verify User Who Owns shadow File

Rule IDxccdf_org.ssgproject.content_rule_userowner_shadow_file
Result
notselected
Time2017-03-14T13:47:48
Severitymedium
Identifiers and References

references:  AC-6, http://iase.disa.mil/stigs/cci/Pages/index.aspx, Req-8.7.c

Description

To properly set the owner of /etc/shadow, run the command:

$ sudo chown root /etc/shadow

Rationale

The /etc/shadow file contains the list of local system accounts and stores password hashes. Protection of this file is critical for system security. Failure to give ownership of this file to root provides the designated owner with access to sensitive information which could weaken the system security posture.

Verify Group Who Owns shadow Filexccdf_org.ssgproject.content_rule_groupowner_shadow_file medium

Verify Group Who Owns shadow File

Rule IDxccdf_org.ssgproject.content_rule_groupowner_shadow_file
Result
notselected
Time2017-03-14T13:47:48
Severitymedium
Identifiers and References

references:  AC-6, http://iase.disa.mil/stigs/cci/Pages/index.aspx, Req-8.7.c

Description

To properly set the group owner of /etc/shadow, run the command:

$ sudo chgrp root /etc/shadow

Rationale

The /etc/shadow file stores password hashes. Protection of this file is critical for system security.

Verify Permissions on shadow Filexccdf_org.ssgproject.content_rule_file_permissions_etc_shadow medium

Verify Permissions on shadow File

Rule IDxccdf_org.ssgproject.content_rule_file_permissions_etc_shadow
Result
notselected
Time2017-03-14T13:47:48
Severitymedium
Identifiers and References

references:  AC-6, http://iase.disa.mil/stigs/cci/Pages/index.aspx, Req-8.7.c

Description

To properly set the permissions of /etc/shadow, run the command:

$ sudo chmod 0000 /etc/shadow

Rationale

The /etc/shadow file contains the list of local system accounts and stores password hashes. Protection of this file is critical for system security. Failure to give ownership of this file to root provides the designated owner with access to sensitive information which could weaken the system security posture.

Verify User Who Owns group Filexccdf_org.ssgproject.content_rule_file_owner_etc_group medium

Verify User Who Owns group File

Rule IDxccdf_org.ssgproject.content_rule_file_owner_etc_group
Result
notselected
Time2017-03-14T13:47:48
Severitymedium
Identifiers and References

references:  AC-6, Req-8.7.c

Description

To properly set the owner of /etc/group, run the command:

$ sudo chown root /etc/group

Rationale

The /etc/group file contains information regarding groups that are configured on the system. Protection of this file is important for system security.

Verify Group Who Owns group Filexccdf_org.ssgproject.content_rule_file_groupowner_etc_group medium

Verify Group Who Owns group File

Rule IDxccdf_org.ssgproject.content_rule_file_groupowner_etc_group
Result
notselected
Time2017-03-14T13:47:48
Severitymedium
Identifiers and References

references:  AC-6, http://iase.disa.mil/stigs/cci/Pages/index.aspx, Req-8.7.c

Description

To properly set the group owner of /etc/group, run the command:

$ sudo chgrp root /etc/group

Rationale

The /etc/group file contains information regarding groups that are configured on the system. Protection of this file is important for system security.

Verify Permissions on group Filexccdf_org.ssgproject.content_rule_file_permissions_etc_group medium

Verify Permissions on group File

Rule IDxccdf_org.ssgproject.content_rule_file_permissions_etc_group
Result
notselected
Time2017-03-14T13:47:48
Severitymedium
Identifiers and References

references:  AC-6, http://iase.disa.mil/stigs/cci/Pages/index.aspx, Req-8.7.c

Description

To properly set the permissions of /etc/group, run the command:

$ sudo chmod 644 /etc/group

Rationale

The /etc/group file contains information regarding groups that are configured on the system. Protection of this file is important for system security.

Verify User Who Owns gshadow Filexccdf_org.ssgproject.content_rule_file_owner_etc_gshadow medium

Verify User Who Owns gshadow File

Rule IDxccdf_org.ssgproject.content_rule_file_owner_etc_gshadow
Result
notselected
Time2017-03-14T13:47:48
Severitymedium
Identifiers and References

references:  AC-6, http://iase.disa.mil/stigs/cci/Pages/index.aspx

Description

To properly set the owner of /etc/gshadow, run the command:

$ sudo chown root /etc/gshadow

Rationale

The /etc/gshadow file contains group password hashes. Protection of this file is critical for system security.

Verify Group Who Owns gshadow Filexccdf_org.ssgproject.content_rule_file_groupowner_etc_gshadow medium

Verify Group Who Owns gshadow File

Rule IDxccdf_org.ssgproject.content_rule_file_groupowner_etc_gshadow
Result
notselected
Time2017-03-14T13:47:48
Severitymedium
Identifiers and References

references:  AC-6, http://iase.disa.mil/stigs/cci/Pages/index.aspx

Description

To properly set the group owner of /etc/gshadow, run the command:

$ sudo chgrp root /etc/gshadow

Rationale

The /etc/gshadow file contains group password hashes. Protection of this file is critical for system security.

Verify Permissions on gshadow Filexccdf_org.ssgproject.content_rule_file_permissions_etc_gshadow medium

Verify Permissions on gshadow File

Rule IDxccdf_org.ssgproject.content_rule_file_permissions_etc_gshadow
Result
notselected
Time2017-03-14T13:47:48
Severitymedium
Identifiers and References

references:  AC-6, http://iase.disa.mil/stigs/cci/Pages/index.aspx

Description

To properly set the permissions of /etc/gshadow, run the command:

$ sudo chmod 0000 /etc/gshadow

Rationale

The /etc/gshadow file contains group password hashes. Protection of this file is critical for system security.

Verify User Who Owns passwd Filexccdf_org.ssgproject.content_rule_file_owner_etc_passwd medium

Verify User Who Owns passwd File

Rule IDxccdf_org.ssgproject.content_rule_file_owner_etc_passwd
Result
notselected
Time2017-03-14T13:47:48
Severitymedium
Identifiers and References

references:  AC-6, http://iase.disa.mil/stigs/cci/Pages/index.aspx, Req-8.7.c

Description

To properly set the owner of /etc/passwd, run the command:

$ sudo chown root /etc/passwd

Rationale

The /etc/passwd file contains information about the users that are configured on the system. Protection of this file is critical for system security.

Verify Group Who Owns passwd Filexccdf_org.ssgproject.content_rule_file_groupowner_etc_passwd medium

Verify Group Who Owns passwd File

Rule IDxccdf_org.ssgproject.content_rule_file_groupowner_etc_passwd
Result
notselected
Time2017-03-14T13:47:48
Severitymedium
Identifiers and References

references:  AC-6, http://iase.disa.mil/stigs/cci/Pages/index.aspx, Req-8.7.c

Description

To properly set the group owner of /etc/passwd, run the command:

$ sudo chgrp root /etc/passwd

Rationale

The /etc/passwd file contains information about the users that are configured on the system. Protection of this file is critical for system security.

Verify Permissions on passwd Filexccdf_org.ssgproject.content_rule_file_permissions_etc_passwd medium

Verify Permissions on passwd File

Rule IDxccdf_org.ssgproject.content_rule_file_permissions_etc_passwd
Result
notselected
Time2017-03-14T13:47:48
Severitymedium
Identifiers and References

references:  AC-6, http://iase.disa.mil/stigs/cci/Pages/index.aspx, Req-8.7.c

Description

To properly set the permissions of /etc/passwd, run the command:

$ sudo chmod 0644 /etc/passwd

Rationale

If the /etc/passwd file is writable by a group-owner or the world the risk of its compromise is increased. The file contains the list of accounts on the system and associated information, and protection of this file is critical for system security.

Verify that Shared Library Files Have Restrictive Permissionsxccdf_org.ssgproject.content_rule_file_permissions_library_dirs medium

Verify that Shared Library Files Have Restrictive Permissions

Rule IDxccdf_org.ssgproject.content_rule_file_permissions_library_dirs
Result
fail
Time2017-03-14T13:48:17
Severitymedium
Identifiers and References

references:  AC-6, http://iase.disa.mil/stigs/cci/Pages/index.aspx

Description

System-wide shared library files, which are linked to executables during process load time or run time, are stored in the following directories by default:

/lib
/lib64
/usr/lib
/usr/lib64
Kernel modules, which can be added to the kernel during runtime, are stored in /lib/modules. All files in these directories should not be group-writable or world-writable. If any file in these directories is found to be group-writable or world-writable, correct its permission with the following command:
$ sudo chmod go-w FILE

Rationale

Files from shared library directories are loaded into the address space of processes (including privileged ones) or of the kernel itself at runtime. Restrictive permissions are necessary to protect the integrity of the system.

Remediation Ansible snippet:   (show)

Complexity:high
Disruption:medium
Strategy:restrict

- name: "Read list of world and group writable files in libraries directories"
  shell: "find /lib /lib64 /usr/lib /usr/lib64 -perm /022 -type f"
  register: world_writable_library_files
  changed_when: False
  failed_when: False

- name: "Disable world/group writability to library files"
  file:
    path: "{{item}}"
    mode: "go-w"
  with_items: "{{ world_writable_library_files.stdout_lines }}"
  when: world_writable_library_files.stdout_lines | length > 0
Verify that Shared Library Files Have Root Ownershipxccdf_org.ssgproject.content_rule_file_ownership_library_dirs medium

Verify that Shared Library Files Have Root Ownership

Rule IDxccdf_org.ssgproject.content_rule_file_ownership_library_dirs
Result
fail
Time2017-03-14T13:48:35
Severitymedium
Identifiers and References

references:  AC-6, http://iase.disa.mil/stigs/cci/Pages/index.aspx

Description

System-wide shared library files, which are linked to executables during process load time or run time, are stored in the following directories by default:

/lib
/lib64
/usr/lib
/usr/lib64
Kernel modules, which can be added to the kernel during runtime, are also stored in /lib/modules. All files in these directories should be owned by the root user. If the directory, or any file in these directories, is found to be owned by a user other than root correct its ownership with the following command:
$ sudo chown root FILE

Rationale

Files from shared library directories are loaded into the address space of processes (including privileged ones) or of the kernel itself at runtime. Proper ownership is necessary to protect the integrity of the system.

Remediation Shell script:   (show)

Complexity:high
Disruption:medium
Strategy:restrict
for LIBDIR in /usr/lib /usr/lib64 /lib /lib64
do
  if [ -d $LIBDIR ]
  then
    find -L $LIBDIR \! -user root -exec chown root {} \; 
  fi
done
Remediation Ansible snippet:   (show)

Complexity:medium
Disruption:medium
Strategy:restrict

- name: "Read list libraries without root ownership"
  shell: "find -L /usr/lib /usr/lib64 /lib /lib64 \\! -user root"
  register: libraries_not_owned_by_root
  changed_when: False
  failed_when: False

- name: "Set ownership of system libraries to root"
  file:
    path: "{{item}}"
    owner: "root"
  with_items: "{{ libraries_not_owned_by_root.stdout_lines }}"
  when: libraries_not_owned_by_root | length > 0
Verify that System Executables Have Restrictive Permissionsxccdf_org.ssgproject.content_rule_file_permissions_binary_dirs medium

Verify that System Executables Have Restrictive Permissions

Rule IDxccdf_org.ssgproject.content_rule_file_permissions_binary_dirs
Result
pass
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-6, http://iase.disa.mil/stigs/cci/Pages/index.aspx

Description

System executables are stored in the following directories by default:

/bin
/sbin
/usr/bin
/usr/libexec
/usr/local/bin
/usr/local/sbin
/usr/sbin
All files in these directories should not be group-writable or world-writable. If any file FILE in these directories is found to be group-writable or world-writable, correct its permission with the following command:
$ sudo chmod go-w FILE

Rationale

System binaries are executed by privileged users, as well as system services, and restrictive permissions are necessary to ensure execution of these programs cannot be co-opted.

Verify that System Executables Have Root Ownershipxccdf_org.ssgproject.content_rule_file_ownership_binary_dirs medium

Verify that System Executables Have Root Ownership

Rule IDxccdf_org.ssgproject.content_rule_file_ownership_binary_dirs
Result
fail
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-6, http://iase.disa.mil/stigs/cci/Pages/index.aspx

Description

System executables are stored in the following directories by default:

/bin
/sbin
/usr/bin
/usr/libexec
/usr/local/bin
/usr/local/sbin
/usr/sbin
All files in these directories should be owned by the root user. If any file FILE in these directories is found to be owned by a user other than root, correct its ownership with the following command:
$ sudo chown root FILE

Rationale

System binaries are executed by privileged users as well as system services, and restrictive permissions are necessary to ensure that their execution of these programs cannot be co-opted.

Remediation Ansible snippet:   (show)

Complexity:medium
Disruption:medium
Strategy:restrict

- name: "Read list of system executables without root ownership"
  shell: "find /bin/ /usr/bin/ /usr/local/bin/ /sbin/ /usr/sbin/ /usr/local/sbin/ /usr/libexec \\! -user root"
  register: no_root_system_executables
  changed_when: False
  failed_when: False

- name: "Set ownership to root of system executables"
  file:
    path: "{{item}}"
    owner: "root"
  with_items: "{{ no_root_system_executables.stdout_lines }}"
  when: no_root_system_executables.stdout_lines | length > 0
Verify that All World-Writable Directories Have Sticky Bits Setxccdf_org.ssgproject.content_rule_dir_perms_world_writable_sticky_bits low

Verify that All World-Writable Directories Have Sticky Bits Set

Rule IDxccdf_org.ssgproject.content_rule_dir_perms_world_writable_sticky_bits
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-6, 1.1.17

Description

When the so-called 'sticky bit' is set on a directory, only the owner of a given file may remove that file from the directory. Without the sticky bit, any user with write access to a directory may remove any file in the directory. Setting the sticky bit prevents users from removing each other's files. In cases where there is no reason for a directory to be world-writable, a better solution is to remove that permission rather than to set the sticky bit. However, if a directory is used by a particular application, consult that application's documentation instead of blindly changing modes.
To set the sticky bit on a world-writable directory DIR, run the following command:

$ sudo chmod +t DIR

Rationale

Failing to set the sticky bit on public directories allows unauthorized users to delete files in the directory structure.

The only authorized public directories are those temporary directories supplied with the system, or those designed to be temporary file repositories. The setting is normally reserved for directories used by the system, by users for temporary file storage (such as /tmp), and for directories requiring global read/write access.

Ensure No World-Writable Files Existxccdf_org.ssgproject.content_rule_file_permissions_unauthorized_world_writable medium

Ensure No World-Writable Files Exist

Rule IDxccdf_org.ssgproject.content_rule_file_permissions_unauthorized_world_writable
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-6

Description

It is generally a good idea to remove global (other) write access to a file when it is discovered. However, check with documentation for specific applications before making changes. Also, monitor for recurring world-writable files, as these may be symptoms of a misconfigured application or user account.

Rationale

Data in world-writable files can be modified by any user on the system. In almost all circumstances, files can be configured using a combination of user and group permissions to support whatever legitimate access is needed without the risk caused by world-writable files.

Ensure All SGID Executables Are Authorizedxccdf_org.ssgproject.content_rule_file_permissions_unauthorized_sgid low

Ensure All SGID Executables Are Authorized

Rule IDxccdf_org.ssgproject.content_rule_file_permissions_unauthorized_sgid
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-6(1)

Description

The SGID (set group id) bit should be set only on files that were installed via authorized means. A straightforward means of identifying unauthorized SGID files is determine if any were not installed as part of an RPM package, which is cryptographically verified. Investigate the origin of any unpackaged SGID files.

Rationale

Executable files with the SGID permission run with the privileges of the owner of the file. SGID files of uncertain provenance could allow for unprivileged users to elevate privileges. The presence of these files should be strictly controlled on the system.

Ensure All SUID Executables Are Authorizedxccdf_org.ssgproject.content_rule_file_permissions_unauthorized_suid low

Ensure All SUID Executables Are Authorized

Rule IDxccdf_org.ssgproject.content_rule_file_permissions_unauthorized_suid
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-6(1)

Description

The SUID (set user id) bit should be set only on files that were installed via authorized means. A straightforward means of identifying unauthorized SGID files is determine if any were not installed as part of an RPM package, which is cryptographically verified. Investigate the origin of any unpackaged SUID files.

Rationale

Executable files with the SUID permission run with the privileges of the owner of the file. SUID files of uncertain provenance could allow for unprivileged users to elevate privileges. The presence of these files should be strictly controlled on the system.

Ensure All Files Are Owned by a Userxccdf_org.ssgproject.content_rule_no_files_unowned_by_user medium

Ensure All Files Are Owned by a User

Rule IDxccdf_org.ssgproject.content_rule_no_files_unowned_by_user
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-6, CM-6(b), 366, SRG-OS-000480-GPOS-00227, 020360

Description

If any files are not owned by a user, then the cause of their lack of ownership should be investigated. Following this, the files should be deleted or assigned to an appropriate user.

Rationale

Unowned files do not directly imply a security problem, but they are generally a sign that something is amiss. They may be caused by an intruder, by incorrect software installation or draft software removal, or by failure to remove all files belonging to a deleted account. The files should be repaired so they will not cause problems when accounts are created in the future, and the cause should be discovered and addressed.

Ensure All Files Are Owned by a Groupxccdf_org.ssgproject.content_rule_file_permissions_ungroupowned medium

Ensure All Files Are Owned by a Group

Rule IDxccdf_org.ssgproject.content_rule_file_permissions_ungroupowned
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-6, IA-2, 366, SRG-OS-000480-GPOS-00227, 020370

Description

If any files are not owned by a group, then the cause of their lack of group-ownership should be investigated. Following this, the files should be deleted or assigned to an appropriate group.

Rationale

Unowned files do not directly imply a security problem, but they are generally a sign that something is amiss. They may be caused by an intruder, by incorrect software installation or draft software removal, or by failure to remove all files belonging to a deleted account. The files should be repaired so they will not cause problems when accounts are created in the future, and the cause should be discovered and addressed.

Ensure All World-Writable Directories Are Owned by a System Accountxccdf_org.ssgproject.content_rule_dir_perms_world_writable_system_owned low

Ensure All World-Writable Directories Are Owned by a System Account

Rule IDxccdf_org.ssgproject.content_rule_dir_perms_world_writable_system_owned
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-6

Description

All directories in local partitions which are world-writable should be owned by root or another system account. If any world-writable directories are not owned by a system account, this should be investigated. Following this, the files should be deleted or assigned to an appropriate group.

Rationale

Allowing a user account to own a world-writable directory is undesirable because it allows the owner of that directory to remove or replace any files that may be placed in the directory by other users.

Set Daemon Umaskxccdf_org.ssgproject.content_rule_umask_for_daemons low

Set Daemon Umask

Rule IDxccdf_org.ssgproject.content_rule_umask_for_daemons
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-6

Description

The file /etc/init.d/functions includes initialization parameters for most or all daemons started at boot time. The default umask of 022 prevents creation of group- or world-writable files. To set the default umask for daemons, edit the following line, inserting 022 or 027 for UMASK appropriately:

umask 022
Setting the umask to too restrictive a setting can cause serious errors at runtime. Many daemons on the system already individually restrict themselves to a umask of 077 in their own init scripts.

Rationale

The umask influences the permissions assigned to files created by a process at run time. An unnecessarily permissive umask could result in files being created with insecure permissions.

Disable Core Dumps for All Usersxccdf_org.ssgproject.content_rule_disable_users_coredumps low

Disable Core Dumps for All Users

Rule IDxccdf_org.ssgproject.content_rule_disable_users_coredumps
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  SC-5

Description

To disable core dumps for all users, add the following line to /etc/security/limits.conf:

*     hard   core    0

Rationale

A core dump includes a memory image taken at the time the operating system terminates an application. The memory image could contain sensitive data and is generally useful only for developers trying to debug problems.

Disable Core Dumps for SUID programsxccdf_org.ssgproject.content_rule_sysctl_fs_suid_dumpable low

Disable Core Dumps for SUID programs

Rule IDxccdf_org.ssgproject.content_rule_sysctl_fs_suid_dumpable
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  SI-11

Description

To set the runtime status of the fs.suid_dumpable kernel parameter, run the following command:

$ sudo sysctl -w fs.suid_dumpable=0
If this is not the system's default value, add the following line to /etc/sysctl.conf:
fs.suid_dumpable = 0

Rationale

The core dump of a setuid program is more likely to contain sensitive data, as the program itself runs with greater privileges than the user who initiated execution of the program. Disabling the ability for any setuid program to write a core file decreases the risk of unauthorized access of such data.

Enable ExecShieldxccdf_org.ssgproject.content_rule_sysctl_kernel_exec_shield medium

Enable ExecShield

Rule IDxccdf_org.ssgproject.content_rule_sysctl_kernel_exec_shield
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  SC-39, 2530

Description

By default on Fedora 64-bit systems, ExecShield is enabled and can only be disabled if the hardware does not support ExecShield or is disabled in /etc/default/grub. For Fedora 32-bit systems, sysctl can be used to enable ExecShield.

Rationale

ExecShield uses the segmentation feature on all x86 systems to prevent execution in memory higher than a certain address. It writes an address as a limit in the code segment descriptor, to control where code can be executed, on a per-process basis. When the kernel places a process's memory regions such as the stack and heap higher than this address, the hardware prevents execution in that address range. This is enabled by default on the latest Red Hat and Fedora systems if supported by the hardware.

Enable Randomized Layout of Virtual Address Spacexccdf_org.ssgproject.content_rule_sysctl_kernel_randomize_va_space medium

Enable Randomized Layout of Virtual Address Space

Rule IDxccdf_org.ssgproject.content_rule_sysctl_kernel_randomize_va_space
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  SC-30(2)

Description

To set the runtime status of the kernel.randomize_va_space kernel parameter, run the following command:

$ sudo sysctl -w kernel.randomize_va_space=2
If this is not the system's default value, add the following line to /etc/sysctl.conf:
kernel.randomize_va_space = 2

Rationale

Address space layout randomization (ASLR) makes it more difficult for an attacker to predict the location of attack code they have introduced into a process's address space during an attempt at exploitation. Additionally, ASLR makes it more difficult for an attacker to know the location of existing code in order to re-purpose it using return oriented programming (ROP) techniques.

Install PAE Kernel on Supported 32-bit x86 Systemsxccdf_org.ssgproject.content_rule_install_PAE_kernel_on_x86-32 low

Install PAE Kernel on Supported 32-bit x86 Systems

Rule IDxccdf_org.ssgproject.content_rule_install_PAE_kernel_on_x86-32
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  CM-6(b)

Description

Systems that are using the 64-bit x86 kernel package do not need to install the kernel-PAE package because the 64-bit x86 kernel already includes this support. However, if the system is 32-bit and also supports the PAE and NX features as determined in the previous section, the kernel-PAE package should be installed to enable XD or NX support:

$ sudo dnf install kernel-PAE
The installation process should also have configured the bootloader to load the new kernel at boot. Verify this at reboot and modify /etc/default/grub if necessary.

Rationale

On 32-bit systems that support the XD or NX bit, the vendor-supplied PAE kernel is required to enable either Execute Disable (XD) or No Execute (NX) support.

Warnings
warning  The kernel-PAE package should not be installed on older systems that do not support the XD or NX bit, as this may prevent them from booting.
Enable NX or XD Support in the BIOSxccdf_org.ssgproject.content_rule_bios_enable_execution_restrictions low

Enable NX or XD Support in the BIOS

Rule IDxccdf_org.ssgproject.content_rule_bios_enable_execution_restrictions
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  CM-6(b)

Description

Reboot the system and enter the BIOS or Setup configuration menu. Navigate the BIOS configuration menu and make sure that the option is enabled. The setting may be located under a Security section. Look for Execute Disable (XD) on Intel-based systems and No Execute (NX) on AMD-based systems.

Rationale

Computers with the ability to prevent this type of code execution frequently put an option in the BIOS that will allow users to turn the feature on or off at will.

Restrict Access to Kernel Message Bufferxccdf_org.ssgproject.content_rule_sysctl_kernel_dmesg_restrict low

Restrict Access to Kernel Message Buffer

Rule IDxccdf_org.ssgproject.content_rule_sysctl_kernel_dmesg_restrict
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  SI-11, 1314

Description

To set the runtime status of the kernel.dmesg_restrict kernel parameter, run the following command:

$ sudo sysctl -w kernel.dmesg_restrict=1
If this is not the system's default value, add the following line to /etc/sysctl.conf:
kernel.dmesg_restrict = 1

Rationale

Unprivileged access to the kernel syslog can expose sensitive kernel address information.

Ensure SELinux Not Disabled in /etc/default/grubxccdf_org.ssgproject.content_rule_enable_selinux_bootloader medium

Ensure SELinux Not Disabled in /etc/default/grub

Rule IDxccdf_org.ssgproject.content_rule_enable_selinux_bootloader
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-3, AC-3(3), AC-6, AU-9, 22, 32

Description

SELinux can be disabled at boot time by an argument in /etc/default/grub. Remove any instances of selinux=0 from the kernel arguments in that file to prevent SELinux from being disabled at boot.

Rationale

Disabling a major host protection feature, such as SELinux, at boot time prevents it from confining system services at boot time. Further, it increases the chances that it will remain off during system operation.

Ensure SELinux State is Enforcingxccdf_org.ssgproject.content_rule_selinux_state medium

Ensure SELinux State is Enforcing

Rule IDxccdf_org.ssgproject.content_rule_selinux_state
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-3, AC-3(3), AC-4, AC-6, AU-9, http://iase.disa.mil/stigs/cci/Pages/index.aspx

Description

The SELinux state should be set to enforcing at system boot time. In the file /etc/selinux/config, add or correct the following line to configure the system to boot into enforcing mode:

SELINUX=enforcing

Rationale

Setting the SELinux state to enforcing ensures SELinux is able to confine potentially compromised processes to the security policy, which is designed to prevent them from causing damage to the system or further elevating their privileges.

Configure SELinux Policyxccdf_org.ssgproject.content_rule_selinux_policytype low

Configure SELinux Policy

Rule IDxccdf_org.ssgproject.content_rule_selinux_policytype
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-3, AC-3(3), AC-4, AC-6, AU-9, http://iase.disa.mil/stigs/cci/Pages/index.aspx

Description

The SELinux targeted policy is appropriate for general-purpose desktops and servers, as well as systems in many other roles. To configure the system to use this policy, add or correct the following line in /etc/selinux/config:

SELINUXTYPE=targeted
Other policies, such as mls, provide additional security labeling and greater confinement but are not compatible with many general-purpose use cases.

Rationale

Setting the SELinux policy to targeted or a more specialized policy ensures the system will confine processes that are likely to be targeted for exploitation, such as network or system services. Note: During the development or debugging of SELinux modules, it is common to temporarily place non-production systems in permissive mode. In such temporary cases, SELinux policies should be developed, and once work is completed, the system should be reconfigured to targeted.

Uninstall setroubleshoot Packagexccdf_org.ssgproject.content_rule_package_setroubleshoot_removed lowCCE-

Uninstall setroubleshoot Package

Rule IDxccdf_org.ssgproject.content_rule_package_setroubleshoot_removed
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

identifiers:  CCE-

Description

The SETroubleshoot service notifies desktop users of SELinux denials. The service provides information around configuration errors, unauthorized intrusions, and other potential errors. The setroubleshoot package can be removed with the following command:

$ sudo dnf erase setroubleshoot

Rationale

The SETroubleshoot service is an unnecessary daemon to have running on a server

Uninstall mcstrans Packagexccdf_org.ssgproject.content_rule_package_mcstrans_removed lowCCE-

Uninstall mcstrans Package

Rule IDxccdf_org.ssgproject.content_rule_package_mcstrans_removed
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

identifiers:  CCE-

Description

The mcstransd daemon provides category label information to client processes requesting information. The label translations are defined in /etc/selinux/targeted/setrans.conf. The mcstrans package can be removed with the following command:

$ sudo dnf erase mcstrans

Rationale

Since this service is not used very often, disable it to reduce the amount of potentially vulnerable code running on the system. NOTE: This rule was added in support of the CIS RHEL6 v1.2.0 benchmark. Please note that Red Hat does not feel this rule is security relevant.

Ensure No Daemons are Unconfined by SELinuxxccdf_org.ssgproject.content_rule_selinux_confinement_of_daemons medium

Ensure No Daemons are Unconfined by SELinux

Rule IDxccdf_org.ssgproject.content_rule_selinux_confinement_of_daemons
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-6, AU-9, CM-7

Description

Daemons for which the SELinux policy does not contain rules will inherit the context of the parent process. Because daemons are launched during startup and descend from the init process, they inherit the initrc_t context.

To check for unconfined daemons, run the following command:

$ sudo ps -eZ | egrep "initrc" | egrep -vw "tr|ps|egrep|bash|awk" | tr ':' ' ' | awk '{ print $NF }'
It should produce no output in a well-configured system.

Rationale

Daemons which run with the initrc_t context may cause AVC denials, or allow privileges that the daemon does not require.

Ensure No Device Files are Unknown to SELinuxxccdf_org.ssgproject.content_rule_selinux_all_devicefiles_labeled low

Ensure No Device Files are Unknown to SELinux

Rule IDxccdf_org.ssgproject.content_rule_selinux_all_devicefiles_labeled
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-6, AU-9, CM-7, 22, 32

Description

Device files, which are used for communication with important system resources, should be labeled with proper SELinux types. If any device files carry the SELinux type device_t, report the bug so that policy can be corrected. Supply information about what the device is and what programs use it.

Rationale

If a device file carries the SELinux type device_t, then SELinux cannot properly restrict access to the device file.

Direct root Logins Not Allowedxccdf_org.ssgproject.content_rule_no_direct_root_logins medium

Direct root Logins Not Allowed

Rule IDxccdf_org.ssgproject.content_rule_no_direct_root_logins
Result
fail
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  IA-2(1)

Description

To further limit access to the root account, administrators can disable root logins at the console by editing the /etc/securetty file. This file lists all devices the root user is allowed to login to. If the file does not exist at all, the root user can login through any communication device on the system, whether via the console or via a raw network interface. This is dangerous as user can login to his machine as root via Telnet, which sends the password in plain text over the network. By default, Fedora's /etc/securetty file only allows the root user to login at the console physically attached to the machine. To prevent root from logging in, remove the contents of this file. To prevent direct root logins, remove the contents of this file by typing the following command:

echo > /etc/securetty

Rationale

Disabling direct root logins ensures proper accountability and multifactor authentication to privileged accounts. Users will first login, then escalate to privileged (root) access via su / sudo. This scenario is nowadays required by security standards.

Remediation Shell script:   (show)

Complexity:high
Disruption:medium
Strategy:restrict
echo > /etc/securetty
Serial Port Root Logins Restrictedxccdf_org.ssgproject.content_rule_restrict_serial_port_logins low

Serial Port Root Logins Restricted

Rule IDxccdf_org.ssgproject.content_rule_restrict_serial_port_logins
Result
pass
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-6(2), 770

Description

To restrict root logins on serial ports, ensure lines of this form do not appear in /etc/securetty:

ttyS0
ttyS1

Rationale

Preventing direct root login to serial port interfaces helps ensure accountability for actions taken on the systems using the root account.

Web Browser Use for Administrative Accounts Restrictedxccdf_org.ssgproject.content_rule_no_root_webbrowsing low

Web Browser Use for Administrative Accounts Restricted

Rule IDxccdf_org.ssgproject.content_rule_no_root_webbrowsing
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References
Description

Enforce policy requiring administrative accounts use web browsers only for local service administration.

Rationale

If a browser vulnerability is exploited while running with administrative privileges, the entire system could be compromised. Specific exceptions for local service administration should be documented in site-defined policy.

System Accounts Do Not Run a Shell Upon Loginxccdf_org.ssgproject.content_rule_no_shelllogin_for_systemaccounts medium

System Accounts Do Not Run a Shell Upon Login

Rule IDxccdf_org.ssgproject.content_rule_no_shelllogin_for_systemaccounts
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-2, CM-6(b), 178

Description

Some accounts are not associated with a human user of the system, and exist to perform some administrative function. Should an attacker be able to log into these accounts, they should not be granted access to a shell.

The login shell for each local account is stored in the last field of each line in /etc/passwd. System accounts are those user accounts with a user ID less than UID_MIN, where value of the UID_MIN directive is set in /etc/login.defs configuration file. In the default configuration UID_MIN is set to 1000, thus system accounts are those user accounts with a user ID less than 1000. The user ID is stored in the third field. If any system account SYSACCT (other than root) has a login shell, disable it with the command:

# usermod -s /sbin/nologin SYSACCT

Rationale

Ensuring shells are not given to system accounts upon login makes it more difficult for attackers to make use of system accounts.

Warnings
warning  Do not perform the steps in this section on the root account. Doing so might cause the system to become inaccessible.
Only Root Has UID 0xccdf_org.ssgproject.content_rule_accounts_no_uid_except_zero medium

Only Root Has UID 0

Rule IDxccdf_org.ssgproject.content_rule_accounts_no_uid_except_zero
Result
pass
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-6, IA-2(1), 366

Description

If any account other than root has a UID of 0, this misconfiguration should be investigated and the accounts other than root should be removed or have their UID changed.

Rationale

An account has root authority if it has a UID of 0. Multiple accounts with a UID of 0 afford more opportunity for potential intruders to guess a password for a privileged account. Proper configuration of sudo is recommended to afford multiple system administrators access to root privileges in an accountable manner.

Root Path Is Vendor Defaultxccdf_org.ssgproject.content_rule_root_path_default low

Root Path Is Vendor Default

Rule IDxccdf_org.ssgproject.content_rule_root_path_default
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References
Description

Assuming root shell is bash, edit the following files:

~/.profile
~/.bashrc
Change any PATH variables to the vendor default for root and remove any empty PATH entries or references to relative paths.

Rationale

The root account's executable search path must be the vendor default, and must contain only absolute paths.

Log In to Accounts With Empty Password Impossiblexccdf_org.ssgproject.content_rule_no_empty_passwords high

Log In to Accounts With Empty Password Impossible

Rule IDxccdf_org.ssgproject.content_rule_no_empty_passwords
Result
fail
Time2017-03-14T13:48:36
Severityhigh
Identifiers and References

references:  IA-5(b), IA-5(c), IA-5(1)(a)

Description

If an account is configured for password authentication but does not have an assigned password, it may be possible to log into the account without authentication. Remove any instances of the nullok option in /etc/pam.d/system-auth to prevent logins with empty passwords.

Rationale

If an account has an empty password, anyone could log in and run commands with the privileges of that account. Accounts with empty passwords should never be used in operational environments.

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:disable
sed --follow-symlinks -i 's/\<nullok\>//g' /etc/pam.d/system-auth
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:medium
Strategy:configure

- name: "Prevent Log In to Accounts With Empty Password"
  replace:
    dest: /etc/pam.d/system-auth
    regexp: 'nullok\s*'
    replace: ''
Password Hashes For Each Account Shadowedxccdf_org.ssgproject.content_rule_accounts_password_all_shadowed medium

Password Hashes For Each Account Shadowed

Rule IDxccdf_org.ssgproject.content_rule_accounts_password_all_shadowed
Result
pass
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  IA-5(h), 201

Description

If any password hashes are stored in /etc/passwd (in the second field, instead of an x), the cause of this misconfiguration should be investigated. The account should have its password reset and the hash should be properly stored, or the account should be deleted entirely.

Rationale

The hashes for all user account passwords should be stored in the file /etc/shadow and never in /etc/passwd, which is readable by all users.

All GIDs referenced in /etc/passwd Defined in /etc/groupxccdf_org.ssgproject.content_rule_gid_passwd_group_same low

All GIDs referenced in /etc/passwd Defined in /etc/group

Rule IDxccdf_org.ssgproject.content_rule_gid_passwd_group_same
Result
pass
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  366

Description

Add a group to the system for each GID referenced without a corresponding group.

Rationale

Inconsistency in GIDs between /etc/passwd and /etc/group could lead to a user having unintended rights.

netrc Files Do Not Existxccdf_org.ssgproject.content_rule_no_netrc_files medium

netrc Files Do Not Exist

Rule IDxccdf_org.ssgproject.content_rule_no_netrc_files
Result
pass
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  IA-5(h), 196

Description

The .netrc files contain login information used to auto-login into FTP servers and reside in the user's home directory. These files may contain unencrypted passwords to remote FTP servers making them susceptible to access by unauthorized users and should not be used. Any .netrc files should be removed.

Rationale

Unencrypted passwords for remote FTP servers may be stored in .netrc files. DoD policy requires passwords be encrypted in storage and not used in access scripts.

Set Password Retry Prompts Permitted Per-Sessionxccdf_org.ssgproject.content_rule_accounts_password_pam_retry low

Set Password Retry Prompts Permitted Per-Session

Rule IDxccdf_org.ssgproject.content_rule_accounts_password_pam_retry
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  IA-5(c), http://iase.disa.mil/stigs/cci/Pages/index.aspx

Description

To configure the number of retry prompts that are permitted per-session:

Edit the pam_pwquality.so statement in /etc/pam.d/system-auth to show retry=3, or a lower value if site policy is more restrictive.

The DoD requirement is a maximum of 3 prompts per session.

Rationale

Setting the password retry prompts that are permitted on a per-session basis to a low value requires some software, such as SSH, to re-connect. This can slow down and draw additional attention to some types of password-guessing attacks. Note that this is different from account lockout, which is provided by the pam_faillock module.

Set Password to Maximum of Three Consecutive Repeating Charactersxccdf_org.ssgproject.content_rule_accounts_password_pam_maxrepeat low

Set Password to Maximum of Three Consecutive Repeating Characters

Rule IDxccdf_org.ssgproject.content_rule_accounts_password_pam_maxrepeat
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  IA-5(c), 366

Description

The pam_pwquality module's maxrepeat parameter controls requirements for consecutive repeating characters. When set to a positive number, it will reject passwords which contain more than that number of consecutive characters. Modify the maxrepeat setting in /etc/security/pwquality.conf to equal 3 to prevent a run of (3 + 1) or more identical characters.

Rationale

Passwords with excessive repeating characters may be more vulnerable to password-guessing attacks.

Set Password to Maximum of Consecutive Repeating Characters from Same Character Classxccdf_org.ssgproject.content_rule_accounts_password_pam_maxclassrepeat lowCCE-

Set Password to Maximum of Consecutive Repeating Characters from Same Character Class

Rule IDxccdf_org.ssgproject.content_rule_accounts_password_pam_maxclassrepeat
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

identifiers:  CCE-

references:  IA-5(c), 366

Description

The pam_pwquality module's maxclassrepeat parameter controls requirements for consecutive repeating characters from the same character class. When set to a positive number, it will reject passwords which contain more than that number of consecutive characters from the same character class. Modify the maxclassrepeat setting in /etc/security/pwquality.conf to equal 2 to prevent a run of (2 + 1) or more identical characters.

Rationale

Passwords with excessive repeating characters from the same character class may be more vulnerable to password-guessing attacks.

Set Password Strength Minimum Digit Charactersxccdf_org.ssgproject.content_rule_accounts_password_pam_dcredit low

Set Password Strength Minimum Digit Characters

Rule IDxccdf_org.ssgproject.content_rule_accounts_password_pam_dcredit
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  IA-5(b), IA-5(c), 194, http://iase.disa.mil/stigs/cci/Pages/index.aspx

Description

The pam_pwquality module's dcredit parameter controls requirements for usage of digits in a password. When set to a negative number, any password will be required to contain that many digits. When set to a positive number, pam_pwquality will grant +1 additional length credit for each digit. Modify the dcredit setting in /etc/security/pwquality.conf to require the use of a digit in passwords.

Rationale

Requiring digits makes password guessing attacks more difficult by ensuring a larger search space.

Set Password Minimum Lengthxccdf_org.ssgproject.content_rule_accounts_password_pam_minlen low

Set Password Minimum Length

Rule IDxccdf_org.ssgproject.content_rule_accounts_password_pam_minlen
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  IA-5(1)(a), 205, 78

Description

The pam_pwquality module's minlen parameter controls requirements for minimum characters required in a password. Add minlen=15 after pam_pwquality to set minimum password length requirements.

Rationale

Password length is one factor of several that helps to determine strength and how long it takes to crack a password. Use of more characters in a password helps to exponentially increase the time and/or resources required to compromise the password.

Set Password Strength Minimum Uppercase Charactersxccdf_org.ssgproject.content_rule_accounts_password_pam_ucredit low

Set Password Strength Minimum Uppercase Characters

Rule IDxccdf_org.ssgproject.content_rule_accounts_password_pam_ucredit
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  IA-5(b), IA-5(c), IA-5(1)(a), http://iase.disa.mil/stigs/cci/Pages/index.aspx

Description

The pam_pwquality module's ucredit= parameter controls requirements for usage of uppercase letters in a password. When set to a negative number, any password will be required to contain that many uppercase characters. When set to a positive number, pam_pwquality will grant +1 additional length credit for each uppercase character. Modify the ucredit setting in /etc/security/pwquality.conf to require the use of an uppercase character in passwords.

Rationale

Requiring a minimum number of uppercase characters makes password guessing attacks more difficult by ensuring a larger search space.

Set Password Strength Minimum Special Charactersxccdf_org.ssgproject.content_rule_accounts_password_pam_ocredit low

Set Password Strength Minimum Special Characters

Rule IDxccdf_org.ssgproject.content_rule_accounts_password_pam_ocredit
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  IA-5(b), IA-5(c), IA-5(1)(a), http://iase.disa.mil/stigs/cci/Pages/index.aspx

Description

The pam_pwquality module's ocredit= parameter controls requirements for usage of special (or "other") characters in a password. When set to a negative number, any password will be required to contain that many special characters. When set to a positive number, pam_pwquality will grant +1 additional length credit for each special character. Modify the ocredit setting in /etc/security/pwquality.conf to equal -1 to require use of a special character in passwords.

Rationale

Requiring a minimum number of special characters makes password guessing attacks more difficult by ensuring a larger search space.

Set Password Strength Minimum Lowercase Charactersxccdf_org.ssgproject.content_rule_accounts_password_pam_lcredit low

Set Password Strength Minimum Lowercase Characters

Rule IDxccdf_org.ssgproject.content_rule_accounts_password_pam_lcredit
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  IA-5(b), IA-5(c), IA-5(1)(a), http://iase.disa.mil/stigs/cci/Pages/index.aspx

Description

The pam_pwquality module's lcredit parameter controls requirements for usage of lowercase letters in a password. When set to a negative number, any password will be required to contain that many lowercase characters. When set to a positive number, pam_pwquality will grant +1 additional length credit for each lowercase character. Modify the lcredit setting in /etc/security/pwquality.conf to require the use of a lowercase character in passwords.

Rationale

Requiring a minimum number of lowercase characters makes password guessing attacks more difficult by ensuring a larger search space.

Set Password Strength Minimum Different Charactersxccdf_org.ssgproject.content_rule_accounts_password_pam_difok low

Set Password Strength Minimum Different Characters

Rule IDxccdf_org.ssgproject.content_rule_accounts_password_pam_difok
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  IA-5(b), IA-5(c), IA-5(1)(b), http://iase.disa.mil/stigs/cci/Pages/index.aspx

Description

The pam_pwquality module's difok parameter controls requirements for usage of different characters during a password change. Modify the difok setting in /etc/security/pwquality.conf to equal 15 to require differing characters when changing passwords. The DoD requirement is 4.

Rationale

Requiring a minimum number of different characters during password changes ensures that newly changed passwords should not resemble previously compromised ones. Note that passwords which are changed on compromised systems will still be compromised, however.

Set Password Strength Minimum Different Categoriesxccdf_org.ssgproject.content_rule_accounts_password_pam_minclass low

Set Password Strength Minimum Different Categories

Rule IDxccdf_org.ssgproject.content_rule_accounts_password_pam_minclass
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References
Description

The pam_pwquality module's minclass parameter controls requirements for usage of different character classes, or types, of character that must exist in a password before it is considered valid. For example, setting this value to three (3) requires that any password must have characters from at least three different categories in order to be approved. The default value is zero (0), meaning there are no required classes. There are four categories available:

* Upper-case characters
* Lower-case characters
* Digits
* Special characters (for example, punctuation)
Modify the minclass setting in /etc/security/pwquality.conf entry to require 3 differing categories of characters when changing passwords. The minimum requirement is 3.

Rationale

Requiring a minimum number of character categories makes password guessing attacks more difficult by ensuring a larger search space.

Set Deny For Failed Password Attemptsxccdf_org.ssgproject.content_rule_accounts_passwords_pam_faillock_deny medium

Set Deny For Failed Password Attempts

Rule IDxccdf_org.ssgproject.content_rule_accounts_passwords_pam_faillock_deny
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-7(a), http://iase.disa.mil/stigs/cci/Pages/index.aspx

Description

To configure the system to lock out accounts after a number of incorrect login attempts using pam_faillock.so, modify the content of both /etc/pam.d/system-auth and /etc/pam.d/password-auth as follows:

  • add the following line immediately before the pam_unix.so statement in the AUTH section:
    auth required pam_faillock.so preauth silent deny=3 unlock_time=604800 fail_interval=900
  • add the following line immediately after the pam_unix.so statement in the AUTH section:
    auth [default=die] pam_faillock.so authfail deny=3 unlock_time=604800 fail_interval=900
  • add the following line immediately before the pam_unix.so statement in the ACCOUNT section:
    account required pam_faillock.so

Rationale

Locking out user accounts after a number of incorrect attempts prevents direct password guessing attacks.

Set Lockout Time For Failed Password Attemptsxccdf_org.ssgproject.content_rule_accounts_passwords_pam_faillock_unlock_time medium

Set Lockout Time For Failed Password Attempts

Rule IDxccdf_org.ssgproject.content_rule_accounts_passwords_pam_faillock_unlock_time
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-7(b), 47

Description

To configure the system to lock out accounts after a number of incorrect login attempts and require an administrator to unlock the account using pam_faillock.so, modify the content of both /etc/pam.d/system-auth and /etc/pam.d/password-auth as follows:

  • add the following line immediately before the pam_unix.so statement in the AUTH section:
    auth required pam_faillock.so preauth silent deny=3 unlock_time=604800 fail_interval=900
  • add the following line immediately after the pam_unix.so statement in the AUTH section:
    auth [default=die] pam_faillock.so authfail deny=3 unlock_time=604800 fail_interval=900
  • add the following line immediately before the pam_unix.so statement in the ACCOUNT section:
    account required pam_faillock.so

Rationale

Locking out user accounts after a number of incorrect attempts prevents direct password guessing attacks. Ensuring that an administrator is involved in unlocking locked accounts draws appropriate attention to such situations.

Set Interval For Counting Failed Password Attemptsxccdf_org.ssgproject.content_rule_accounts_passwords_pam_faillock_interval medium

Set Interval For Counting Failed Password Attempts

Rule IDxccdf_org.ssgproject.content_rule_accounts_passwords_pam_faillock_interval
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-7(a), 1452

Description

Utilizing pam_faillock.so, the fail_interval directive configures the system to lock out accounts after a number of incorrect login attempts. Modify the content of both /etc/pam.d/system-auth and /etc/pam.d/password-auth as follows:

  • add the following line immediately before the pam_unix.so statement in the AUTH section:
    auth required pam_faillock.so preauth silent deny=3 unlock_time=604800 fail_interval=900
  • add the following line immediately after the pam_unix.so statement in the AUTH section:
    auth [default=die] pam_faillock.so authfail deny=3 unlock_time=604800 fail_interval=900
  • add the following line immediately before the pam_unix.so statement in the ACCOUNT section:
    account required pam_faillock.so

Rationale

Locking out user accounts after a number of incorrect attempts within a specific period of time prevents direct password guessing attacks.

Limit Password Reusexccdf_org.ssgproject.content_rule_accounts_password_pam_unix_remember medium

Limit Password Reuse

Rule IDxccdf_org.ssgproject.content_rule_accounts_password_pam_unix_remember
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  IA-5(f), IA-5(1)(e), http://iase.disa.mil/stigs/cci/Pages/index.aspx

Description

Do not allow users to reuse recent passwords. This can be accomplished by using the remember option for the pam_unix or pam_pwhistory PAM modules. In the file /etc/pam.d/system-auth, append remember=24 to the line which refers to the pam_unix.so or pam_pwhistory.somodule, as shown below:

  • for the pam_unix.so case:
    password sufficient pam_unix.so existing_options remember=24
  • for the pam_pwhistory.so case:
    password requisite pam_pwhistory.so existing_options remember=24

Rationale

Preventing re-use of previous passwords helps ensure that a compromised password is not re-used by a user.

Set Password Hashing Algorithm in /etc/pam.d/system-authxccdf_org.ssgproject.content_rule_set_password_hashing_algorithm_systemauth medium

Set Password Hashing Algorithm in /etc/pam.d/system-auth

Rule IDxccdf_org.ssgproject.content_rule_set_password_hashing_algorithm_systemauth
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  IA-5(b), IA-5(c), IA-5(1)(c), IA-7, http://iase.disa.mil/stigs/cci/Pages/index.aspx

Description

In /etc/pam.d/system-auth, the password section of the file controls which PAM modules execute during a password change. Set the pam_unix.so module in the password section to include the argument sha512, as shown below:

password    sufficient    pam_unix.so sha512 other arguments...
This will help ensure when local users change their passwords, hashes for the new passwords will be generated using the SHA-512 algorithm. This is the default.

Rationale

Using a stronger hashing algorithm makes password cracking attacks more difficult.

Set Password Hashing Algorithm in /etc/login.defsxccdf_org.ssgproject.content_rule_set_password_hashing_algorithm_logindefs medium

Set Password Hashing Algorithm in /etc/login.defs

Rule IDxccdf_org.ssgproject.content_rule_set_password_hashing_algorithm_logindefs
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  IA-5(b), IA-5(c), IA-5(1)(c), IA-7, http://iase.disa.mil/stigs/cci/Pages/index.aspx

Description

In /etc/login.defs, add or correct the following line to ensure the system will use SHA-512 as the hashing algorithm:

ENCRYPT_METHOD SHA512

Rationale

Using a stronger hashing algorithm makes password cracking attacks more difficult.

Set Password Hashing Algorithm in /etc/libuser.confxccdf_org.ssgproject.content_rule_set_password_hashing_algorithm_libuserconf medium

Set Password Hashing Algorithm in /etc/libuser.conf

Rule IDxccdf_org.ssgproject.content_rule_set_password_hashing_algorithm_libuserconf
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  IA-5(b), IA-5(c), IA-5(1)(c), IA-7, http://iase.disa.mil/stigs/cci/Pages/index.aspx

Description

In /etc/libuser.conf, add or correct the following line in its [defaults] section to ensure the system will use the SHA-512 algorithm for password hashing:

crypt_style = sha512

Rationale

Using a stronger hashing algorithm makes password cracking attacks more difficult.

Ensure that Root's Path Does Not Include Relative Paths or Null Directoriesxccdf_org.ssgproject.content_rule_root_path_no_dot low

Ensure that Root's Path Does Not Include Relative Paths or Null Directories

Rule IDxccdf_org.ssgproject.content_rule_root_path_no_dot
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  CM-6(b), 366

Description

Ensure that none of the directories in root's path is equal to a single . character, or that it contains any instances that lead to relative path traversal, such as .. or beginning a path without the slash (/) character. Also ensure that there are no "empty" elements in the path, such as in these examples:

PATH=:/bin
PATH=/bin:
PATH=/bin::/sbin
These empty elements have the same effect as a single . character.

Rationale

Including these entries increases the risk that root could execute code from an untrusted location.

Ensure that Root's Path Does Not Include World or Group-Writable Directoriesxccdf_org.ssgproject.content_rule_accounts_root_path_dirs_no_write low

Ensure that Root's Path Does Not Include World or Group-Writable Directories

Rule IDxccdf_org.ssgproject.content_rule_accounts_root_path_dirs_no_write
Result
pass
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  CM-6(b), 366

Description

For each element in root's path, run:

$ sudo ls -ld DIR
and ensure that write permissions are disabled for group and other.

Rationale

Such entries increase the risk that root could execute code provided by unprivileged users, and potentially malicious code.

Ensure the Default Bash Umask is Set Correctlyxccdf_org.ssgproject.content_rule_accounts_umask_bashrc low

Ensure the Default Bash Umask is Set Correctly

Rule IDxccdf_org.ssgproject.content_rule_accounts_umask_bashrc
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  SA-8, 366

Description

To ensure the default umask for users of the Bash shell is set properly, add or correct the umask setting in /etc/bashrc to read as follows:

umask 027

Rationale

The umask value influences the permissions assigned to files when they are created. A misconfigured umask value could result in files with excessive permissions that can be read or written to by unauthorized users.

Ensure the Default C Shell Umask is Set Correctlyxccdf_org.ssgproject.content_rule_accounts_umask_cshrc low

Ensure the Default C Shell Umask is Set Correctly

Rule IDxccdf_org.ssgproject.content_rule_accounts_umask_cshrc
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  SA-8, 366

Description

To ensure the default umask for users of the C shell is set properly, add or correct the umask setting in /etc/csh.cshrc to read as follows:

umask 027

Rationale

The umask value influences the permissions assigned to files when they are created. A misconfigured umask value could result in files with excessive permissions that can be read or written to by unauthorized users.

Ensure the Default Umask is Set Correctly in /etc/profilexccdf_org.ssgproject.content_rule_accounts_umask_etc_profile low

Ensure the Default Umask is Set Correctly in /etc/profile

Rule IDxccdf_org.ssgproject.content_rule_accounts_umask_etc_profile
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  SA-8, 366

Description

To ensure the default umask controlled by /etc/profile is set properly, add or correct the umask setting in /etc/profile to read as follows:

umask 027

Rationale

The umask value influences the permissions assigned to files when they are created. A misconfigured umask value could result in files with excessive permissions that can be read or written to by unauthorized users.

Ensure that User Home Directories are not Group-Writable or World-Readablexccdf_org.ssgproject.content_rule_file_permissions_home_dirs low

Ensure that User Home Directories are not Group-Writable or World-Readable

Rule IDxccdf_org.ssgproject.content_rule_file_permissions_home_dirs
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-6(7), 225

Description

For each human user of the system, view the permissions of the user's home directory:

$ sudo ls -ld /home/USER
Ensure that the directory is not group-writable and that it is not world-readable. If necessary, repair the permissions:
$ sudo chmod g-w /home/USER
$ sudo chmod o-rwx /home/USER

Rationale

User home directories contain many configuration files which affect the behavior of a user's account. No user should ever have write permission to another user's home directory. Group shared directories can be configured in sub-directories or elsewhere in the filesystem if they are needed. Typically, user home directories should not be world-readable, as it would disclose file names to other users. If a subset of users need read access to one another's home directories, this can be provided using groups or ACLs.

Warnings
warning  This action may involve modifying user home directories. Notify your user community, and solicit input if appropriate, before making this type of change.
Verify /boot/grub2/grub.cfg User Ownershipxccdf_org.ssgproject.content_rule_file_user_owner_grub2_cfg medium

Verify /boot/grub2/grub.cfg User Ownership

Rule IDxccdf_org.ssgproject.content_rule_file_user_owner_grub2_cfg
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-6(7), 225, Req-7.1, 1.5.1

Description

The file /boot/grub2/grub.cfg should be owned by the root user to prevent destruction or modification of the file. To properly set the owner of /boot/grub2/grub.cfg, run the command:

$ sudo chown root /boot/grub2/grub.cfg

Rationale

Only root should be able to modify important boot parameters.

Verify /boot/grub2/grub.cfg Group Ownershipxccdf_org.ssgproject.content_rule_file_group_owner_grub2_cfg medium

Verify /boot/grub2/grub.cfg Group Ownership

Rule IDxccdf_org.ssgproject.content_rule_file_group_owner_grub2_cfg
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-6(7), 225, Req-7.1, 1.5.1

Description

The file /boot/grub2/grub.cfg should be group-owned by the root group to prevent destruction or modification of the file. To properly set the group owner of /boot/grub2/grub.cfg, run the command:

$ sudo chgrp root /boot/grub2/grub.cfg

Rationale

The root group is a highly-privileged group. Furthermore, the group-owner of this file should not have any access privileges anyway.

Verify /boot/grub2/grub.cfg Permissionsxccdf_org.ssgproject.content_rule_file_permissions_grub2_cfg medium

Verify /boot/grub2/grub.cfg Permissions

Rule IDxccdf_org.ssgproject.content_rule_file_permissions_grub2_cfg
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-6(7), 225, 1.5.2

Description

File permissions for /boot/grub2/grub.cfg should be set to 600, which is the default. To properly set the permissions of /boot/grub2/grub.cfg, run the command:

$ sudo chmod 600 /boot/grub2/grub.cfg

Rationale

Proper permissions ensure that only the root user can modify important boot parameters.

Set Boot Loader Passwordxccdf_org.ssgproject.content_rule_bootloader_password medium

Set Boot Loader Password

Rule IDxccdf_org.ssgproject.content_rule_bootloader_password
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  IA-2(1), IA-5(e), AC-3, 213, 1.5.3

Description

The grub2 boot loader should have a superuser account and password protection enabled to protect boot-time settings.

To do so, select a superuser account and password and add them into the /etc/grub.d/01_users configuration file.

Since plaintext passwords are a security risk, generate a hash for the pasword by running the following command:

$ grub2-mkpasswd-pbkdf2
When prompted, enter the password that was selected and insert the returned password hash into the /etc/grub.d/01_users configuration file immediately after the superuser account. (Use the output from grub2-mkpasswd-pbkdf2 as the value of password-hash):
password_pbkdf2 superusers-account password-hash
NOTE: It is recommended not to use common administrator account names like root, admin, or administrator for the grub2 superuser account.

To meet FISMA Moderate, the bootloader superuser account and password MUST differ from the root account and password. Once the superuser account and password have been added, update the grub.cfg file by running:
grub2-mkconfig -o /boot/grub2/grub.cfg
NOTE: Do NOT manually add the superuser account and password to the grub.cfg file as the grub2-mkconfig command overwrites this file.

Rationale

Password protection on the boot loader configuration ensures users with physical access cannot trivially alter important bootloader settings. These include which kernel to use, and whether to enter single-user mode. For more information on how to configure the grub2 superuser account and password, please refer to

Set the UEFI Boot Loader Passwordxccdf_org.ssgproject.content_rule_bootloader_uefi_password medium

Set the UEFI Boot Loader Password

Rule IDxccdf_org.ssgproject.content_rule_bootloader_uefi_password
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-3, 213

Description

The UEFI grub2 boot loader should have a superuser account and password protection enabled to protect boot-time settings.

To do so, select a superuser account and password and add them into the /etc/grub.d/01_users configuration file.

Since plaintext passwords are a security risk, generate a hash for the pasword by running the following command:

$ grub2-mkpasswd-pbkdf2
When prompted, enter the password that was selected and insert the returned password hash into the /etc/grub.d/01_users configuration file immediately after the superuser account. (Use the output from grub2-mkpasswd-pbkdf2 as the value of password-hash):
password_pbkdf2 superusers-account password-hash
NOTE: It is recommended not to use common administrator account names like root, admin, or administrator for the grub2 superuser account.

To meet FISMA Moderate, the bootloader superuser account and password MUST differ from the root account and password. Once the superuser account and password have been added, update the grub.cfg file by running:
grub2-mkconfig -o /boot/efi/EFI/fedora/grub.cfg
NOTE: Do NOT manually add the superuser account and password to the grub.cfg file as the grub2-mkconfig command overwrites this file.

Rationale

Password protection on the boot loader configuration ensures users with physical access cannot trivially alter important bootloader settings. These include which kernel to use, and whether to enter single-user mode.

Install the screen Packagexccdf_org.ssgproject.content_rule_package_screen_installed medium

Install the screen Package

Rule IDxccdf_org.ssgproject.content_rule_package_screen_installed
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-11(a), 57

Description

To enable console screen locking, install the screen package:

        The screen package can be installed with the following command:
        
$ sudo dnf install screen
Instruct users to begin new terminal sessions with the following command:
$ screen
The console can now be locked with the following key combination:
ctrl+a x

Rationale

A session time-out lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but des not logout because of the temporary nature of the absence. Rather than relying on the user to manually lock their operation system session prior to vacating the vicinity, operating systems need to be able to identify when a user's session has idled and take action to initiate the session lock. The screen package allows for a session lock to be implemented and configured.

Enable Smart Card Loginxccdf_org.ssgproject.content_rule_smartcard_auth medium

Enable Smart Card Login

Rule IDxccdf_org.ssgproject.content_rule_smartcard_auth
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  765, 766, 767, 768, 771, 772, 884, Req-8.3

Description
Rationale

Smart card login provides two-factor authentication stronger than that provided by a username and password combination. Smart cards leverage PKI (public key infrastructure) in order to provide and verify credentials.

Require Authentication for Single User Modexccdf_org.ssgproject.content_rule_require_singleuser_auth medium

Require Authentication for Single User Mode

Rule IDxccdf_org.ssgproject.content_rule_require_singleuser_auth
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  IA-2(1), AC-3, 213

Description

Single-user mode is intended as a system recovery method, providing a single user root access to the system by providing a boot option at startup. By default, no authentication is performed if single-user mode is selected.

By default, single-user mode is protected by requiring a password and is set in /usr/lib/systemd/system/rescue.service.

Rationale

This prevents attackers with physical access from trivially bypassing security on the machine and gaining root access. Such accesses are further prevented by configuring the bootloader password.

Disable debug-shell SystemD Servicexccdf_org.ssgproject.content_rule_service_debug-shell_disabled medium

Disable debug-shell SystemD Service

Rule IDxccdf_org.ssgproject.content_rule_service_debug-shell_disabled
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References
Description

SystemD's debug-shell service is intended to diagnose SystemD related boot issues with various systemctl commands. Once enabled and following a system reboot, the root shell will be available on tty9 which is access by pressing CTRL-ALT-F9. The debug-shell service should only be used for SystemD related issues and should otherwise be disabled.

By default, the debug-shell SystemD service is disabled. The debug-shell service can be disabled with the following command:

$ sudo systemctl disable debug-shell.service

Rationale

This prevents attackers with physical access from trivially bypassing security on the machine through valid troubleshooting configurations and gaining root access when the system is rebooted.

Disable Ctrl-Alt-Del Reboot Activationxccdf_org.ssgproject.content_rule_disable_ctrlaltdel_reboot high

Disable Ctrl-Alt-Del Reboot Activation

Rule IDxccdf_org.ssgproject.content_rule_disable_ctrlaltdel_reboot
Result
notselected
Time2017-03-14T13:48:36
Severityhigh
Identifiers and References

references:  AC-6, 366

Description

By default, SystemD will reboot the system if the Ctrl-Alt-Del key sequence is pressed.
To configure the system to ignore the Ctrl-Alt-Del key sequence from the command line instead of rebooting the system, do either of the following:

ln -sf /dev/null /etc/systemd/system/ctrl-alt-del.target
or
systemctl mask ctrl-alt-del.target

Do not simply delete the /usr/lib/systemd/system/ctrl-alt-del.service file, as this file may be restored during future system updates.

Rationale

A locally logged-in user who presses Ctrl-Alt-Del, when at the console, can reboot the system. If accidentally pressed, as could happen in the case of mixed OS environment, this can create the risk of short-term loss of availability of systems due to unintentional reboot.

Verify that Interactive Boot is Disabledxccdf_org.ssgproject.content_rule_disable_interactive_boot medium

Verify that Interactive Boot is Disabled

Rule IDxccdf_org.ssgproject.content_rule_disable_interactive_boot
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  SC-2, AC-3, 213

Description

Fedora systems support an "interactive boot" option that can be used to prevent services from being started. On a Fedora system, interactive boot can be enabled by providing a 1, yes, true, or on value to the systemd.confirm_spawn kernel argument in /etc/default/grub. Remove any instance of

systemd.confirm_spawn=(1|yes|true|on)
from the kernel arguments in that file to disable interactive boot.

Rationale

Using interactive boot, the console user could disable auditing, firewalls, or other services, weakening system security.

Warnings
warning  The GRUB 2 configuration file, grub.cfg, is automatically updated each time a new kernel is installed. Note that any changes to /etc/default/grub require rebuilding the grub.cfg file. To update the GRUB 2 configuration file manually, use the
grub2-mkconfig -o
command as follows:
  • On BIOS-based machines, issue the following command as root:
    ~]# grub2-mkconfig -o /boot/grub2/grub.cfg
  • On UEFI-based machines, issue the following command as root:
    ~]# grub2-mkconfig -o /boot/efi/EFI/redhat/grub.cfg
Enable GNOME3 Login Warning Bannerxccdf_org.ssgproject.content_rule_dconf_gnome_banner_enabled medium

Enable GNOME3 Login Warning Banner

Rule IDxccdf_org.ssgproject.content_rule_dconf_gnome_banner_enabled
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-8(a), AC-8(b), AC-8(c), 48, 50

Description

To enable displaying a login warning banner in the GNOME Display Manager's login screen, the banner-message-enable setting must be set under an appropriate configuration file(s) in the /etc/dconf/db/gdm.d directory and locked in /etc/dconf/db/gdm.d/locks directory to prevent user modification. After the settings have been set, run dconf update. To display a banner, this setting must be enabled, and the user must be prevented from making changes. The banner text must also be set.

Rationale

An appropriate warning message reinforces policy awareness during the logon process and facilitates possible legal action against attackers.

Modify the System Login Bannerxccdf_org.ssgproject.content_rule_banner_etc_issue medium

Modify the System Login Banner

Rule IDxccdf_org.ssgproject.content_rule_banner_etc_issue
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-8(a), AC-8(b), AC-8(c), 48, 1384, 1385, 1386, 1387, 1388

Description

To configure the system login banner:

Edit /etc/issue. Replace the default text with a message compliant with the local site policy or a legal disclaimer. The DoD required text is either:

You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions:
-The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations.
-At any time, the USG may inspect and seize data stored on this IS.
-Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose.
-This IS includes security measures (e.g., authentication and access controls) to protect USG interests -- not for your personal benefit or privacy.
-Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details.


OR:

I've read & consent to terms in IS user agreem't.

Rationale

An appropriate warning message reinforces policy awareness during the logon process and facilitates possible legal action against attackers.

Disable Kernel Parameter for Sending ICMP Redirects by Defaultxccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_default_send_redirects medium

Disable Kernel Parameter for Sending ICMP Redirects by Default

Rule IDxccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_default_send_redirects
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-4, CM-7, SC-5, SC-7, 1551, 4.1.2

Description

To set the runtime status of the net.ipv4.conf.default.send_redirects kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.default.send_redirects=0
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv4.conf.default.send_redirects = 0

Rationale

ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages contain information from the system's route table possibly revealing portions of the network topology.
The ability to send ICMP redirects is only appropriate for systems acting as routers.

Disable Kernel Parameter for Sending ICMP Redirects for All Interfacesxccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_all_send_redirects medium

Disable Kernel Parameter for Sending ICMP Redirects for All Interfaces

Rule IDxccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_all_send_redirects
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  CM-7, SC-5(1), 1551, 4.1.2

Description

To set the runtime status of the net.ipv4.conf.all.send_redirects kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.all.send_redirects=0
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv4.conf.all.send_redirects = 0

Rationale

ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages contain information from the system's route table possibly revealing portions of the network topology.
The ability to send ICMP redirects is only appropriate for systems acting as routers.

Disable Kernel Parameter for IP Forwardingxccdf_org.ssgproject.content_rule_sysctl_net_ipv4_ip_forward medium

Disable Kernel Parameter for IP Forwarding

Rule IDxccdf_org.ssgproject.content_rule_sysctl_net_ipv4_ip_forward
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  CM-7, SC-5, 366, 4.1.1

Description

To set the runtime status of the net.ipv4.ip_forward kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.ip_forward=0
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv4.ip_forward = 0

Rationale

IP forwarding permits the kernel to forward packets from one network interface to another. The ability to forward packets between two networks is only appropriate for systems acting as routers.

Configure Kernel Parameter for Accepting Source-Routed Packets for All Interfacesxccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_all_accept_source_route medium

Configure Kernel Parameter for Accepting Source-Routed Packets for All Interfaces

Rule IDxccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_all_accept_source_route
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-4, CM-7, SC-5, 366, SRG-OS-000480-GPOS-00227, 040350, 4.2.1

Description

To set the runtime status of the net.ipv4.conf.all.accept_source_route kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.all.accept_source_route=0
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv4.conf.all.accept_source_route = 0

Rationale

Source-routed packets allow the source of the packet to suggest routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the forwarding of source-routerd traffic, such as when IPv4 forwarding is enabled and the system is functioning as a router. Accepting source-routed packets in the IPv4 protocol has few legitimate uses. It should be disabled unless it is absolutely required.

Configure Kernel Parameter for Accepting ICMP Redirects for All Interfacesxccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_all_accept_redirects medium

Configure Kernel Parameter for Accepting ICMP Redirects for All Interfaces

Rule IDxccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_all_accept_redirects
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  CM-7, SC-5, 1503, 1551, 4.2.2

Description

To set the runtime status of the net.ipv4.conf.all.accept_redirects kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.all.accept_redirects=0
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv4.conf.all.accept_redirects = 0

Rationale

ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages modify the host's route table and are unauthenticated. An illicit ICMP redirect message could result in a man-in-the-middle attack.
This feature of the IPv4 protocol has few legitimate uses. It should be disabled unless absolutely required.

Configure Kernel Parameter for Accepting Secure Redirects for All Interfacesxccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_all_secure_redirects medium

Configure Kernel Parameter for Accepting Secure Redirects for All Interfaces

Rule IDxccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_all_secure_redirects
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-4, CM-7, SC-5, 1503, 1551, 4.2.3

Description

To set the runtime status of the net.ipv4.conf.all.secure_redirects kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.all.secure_redirects=0
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv4.conf.all.secure_redirects = 0

Rationale

Accepting "secure" ICMP redirects (from those gateways listed as default gateways) has few legitimate uses. It should be disabled unless it is absolutely required.

Configure Kernel Parameter to Log Martian Packetsxccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_all_log_martians low

Configure Kernel Parameter to Log Martian Packets

Rule IDxccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_all_log_martians
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-17(7), CM-7, SC-5(3), 126, 4.2.4

Description

To set the runtime status of the net.ipv4.conf.all.log_martians kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.all.log_martians=1
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv4.conf.all.log_martians = 1

Rationale

The presence of "martian" packets (which have impossible addresses) as well as spoofed packets, source-routed packets, and redirects could be a sign of nefarious network activity. Logging these packets enables this activity to be detected.

Configure Kernel Parameter to Log Martian Packets By Defaultxccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_default_log_martians low

Configure Kernel Parameter to Log Martian Packets By Default

Rule IDxccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_default_log_martians
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-17(7), CM-7, SC-5(3), 126, 4.2.4

Description

To set the runtime status of the net.ipv4.conf.default.log_martians kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.default.log_martians=1
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv4.conf.default.log_martians = 1

Rationale

The presence of "martian" packets (which have impossible addresses) as well as spoofed packets, source-routed packets, and redirects could be a sign of nefarious network activity. Logging these packets enables this activity to be detected.

Configure Kernel Parameter for Accepting Source-Routed Packets By Defaultxccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_default_accept_source_route medium

Configure Kernel Parameter for Accepting Source-Routed Packets By Default

Rule IDxccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_default_accept_source_route
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-4, CM-7, SC-5, SC-7, 1551, SRG-OS-000480-GPOS-00227, 040350, 4.2.1

Description

To set the runtime status of the net.ipv4.conf.default.accept_source_route kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.default.accept_source_route=0
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv4.conf.default.accept_source_route = 0

Rationale

Source-routed packates allow the source of the packet to suggest routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures.
Accepting source-routed packets in the IPv4 protocol has few legitimate uses. It should be disabled unless it is absolutely required, such as when IPv4 forwarding is enabled and the system is legitimately functioning as a router.

Configure Kernel Parameter for Accepting ICMP Redirects By Defaultxccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_default_accept_redirects medium

Configure Kernel Parameter for Accepting ICMP Redirects By Default

Rule IDxccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_default_accept_redirects
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-4, CM-7, SC-5, SC-7, 1551, 4.2.2

Description

To set the runtime status of the net.ipv4.conf.default.accept_redirects kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.default.accept_redirects=0
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv4.conf.default.accept_redirects = 0

Rationale

ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages modify the host's route table and are unauthenticated. An illicit ICMP redirect message could result in a man-in-the-middle attack.
This feature of the IPv4 protocol has few legitimate uses. It should be disabled unless absolutely required.

Configure Kernel Parameter for Accepting Secure Redirects By Defaultxccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_default_secure_redirects medium

Configure Kernel Parameter for Accepting Secure Redirects By Default

Rule IDxccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_default_secure_redirects
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-4, CM-7, SC-5, SC-7, 1551, 4.2.3

Description

To set the runtime status of the net.ipv4.conf.default.secure_redirects kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.default.secure_redirects=0
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv4.conf.default.secure_redirects = 0

Rationale

Accepting "secure" ICMP redirects (from those gateways listed as default gateways) has few legitimate uses. It should be disabled unless it is absolutely required.

Configure Kernel Parameter to Ignore ICMP Broadcast Echo Requestsxccdf_org.ssgproject.content_rule_sysctl_net_ipv4_icmp_echo_ignore_broadcasts medium

Configure Kernel Parameter to Ignore ICMP Broadcast Echo Requests

Rule IDxccdf_org.ssgproject.content_rule_sysctl_net_ipv4_icmp_echo_ignore_broadcasts
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-4, CM-7, SC-5, 366, SRG-OS-000480-GPOS-00227, 040380, 4.2.5

Description

To set the runtime status of the net.ipv4.icmp_echo_ignore_broadcasts kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.icmp_echo_ignore_broadcasts=1
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv4.icmp_echo_ignore_broadcasts = 1

Rationale

Responding to broadcast (ICMP) echoes facilitates network mapping and provides a vector for amplification attacks.
Ignoring ICMP echo requests (pings) sent to broadcast or multicast addresses makes the system slightly more difficult to enumerate on the network.

Configure Kernel Parameter to Ignore Bogus ICMP Error Responsesxccdf_org.ssgproject.content_rule_sysctl_net_ipv4_icmp_ignore_bogus_error_responses low

Configure Kernel Parameter to Ignore Bogus ICMP Error Responses

Rule IDxccdf_org.ssgproject.content_rule_sysctl_net_ipv4_icmp_ignore_bogus_error_responses
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  CM-7, SC-5, 4.2.6

Description

To set the runtime status of the net.ipv4.icmp_ignore_bogus_error_responses kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.icmp_ignore_bogus_error_responses=1
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv4.icmp_ignore_bogus_error_responses = 1

Rationale

Ignoring bogus ICMP error responses reduces log size, although some activity would not be logged.

Configure Kernel Parameter to Use TCP Syncookiesxccdf_org.ssgproject.content_rule_sysctl_net_ipv4_tcp_syncookies medium

Configure Kernel Parameter to Use TCP Syncookies

Rule IDxccdf_org.ssgproject.content_rule_sysctl_net_ipv4_tcp_syncookies
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-4, SC-5(1)(2), SC-5(2), SC-5(3), 366, SRG-OS-000480-GPOS-00227, 040430, 4.2.8

Description

To set the runtime status of the net.ipv4.tcp_syncookies kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.tcp_syncookies=1
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv4.tcp_syncookies = 1

Rationale

A TCP SYN flood attack can cause a denial of service by filling a system's TCP connection table with connections in the SYN_RCVD state. Syncookies can be used to track a connection when a subsequent ACK is received, verifying the initiator is attempting a valid connection and is not a flood source. This feature is activated when a flood condition is detected, and enables the system to continue servicing valid connection requests.

Configure Kernel Parameter to Use Reverse Path Filtering for All Interfacesxccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_all_rp_filter medium

Configure Kernel Parameter to Use Reverse Path Filtering for All Interfaces

Rule IDxccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_all_rp_filter
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-4, SC-5, SC-7, 1551, 4.2.7

Description

To set the runtime status of the net.ipv4.conf.all.rp_filter kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.all.rp_filter=1
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv4.conf.all.rp_filter = 1

Rationale

Enabling reverse path filtering drops packets with source addresses that should not have been able to be received on the interface they were received on. It should not be used on systems which are routers for complicated networks, but is helpful for end hosts and routers serving small networks.

Configure Kernel Parameter to Use Reverse Path Filtering by Defaultxccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_default_rp_filter medium

Configure Kernel Parameter to Use Reverse Path Filtering by Default

Rule IDxccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_default_rp_filter
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-4, SC-5, SC-7, 4.2.7

Description

To set the runtime status of the net.ipv4.conf.default.rp_filter kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.default.rp_filter=1
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv4.conf.default.rp_filter = 1

Rationale

Enabling reverse path filtering drops packets with source addresses that should not have been able to be received on the interface they were received on. It should not be used on systems which are routers for complicated networks, but is helpful for end hosts and routers serving small networks.

Disable WiFi or Bluetooth in BIOSxccdf_org.ssgproject.content_rule_wireless_disable_in_bios low

Disable WiFi or Bluetooth in BIOS

Rule IDxccdf_org.ssgproject.content_rule_wireless_disable_in_bios
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-17(8), AC-18(a), AC-18(d), AC-18(3), CM-7, 85

Description

Some systems that include built-in wireless support offer the ability to disable the device through the BIOS. This is system-specific; consult your hardware manual or explore the BIOS setup during boot.

Rationale

Disabling wireless support in the BIOS prevents easy activation of the wireless interface, generally requiring administrators to reboot the system first.

Deactivate Wireless Network Interfacesxccdf_org.ssgproject.content_rule_wireless_disable_interfaces low

Deactivate Wireless Network Interfaces

Rule IDxccdf_org.ssgproject.content_rule_wireless_disable_interfaces
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-17(8), AC-18(a), AC-18(d), AC-18(3), CM-7, 85, 4.3.1

Description

Deactivating wireless network interfaces should prevent normal usage of the wireless capability.

First, identify the interfaces available with the command:

$ ifconfig -a
Additionally, the following command may be used to determine whether wireless support is included for a particular interface, though this may not always be a clear indicator:
$ iwconfig
After identifying any wireless interfaces (which may have names like wlan0, ath0, wifi0, em1 or eth0), deactivate the interface with the command:
$ sudo ifdown interface
These changes will only last until the next reboot. To disable the interface for future boots, remove the appropriate interface file from /etc/sysconfig/network-scripts:
$ sudo rm /etc/sysconfig/network-scripts/ifcfg-interface

Rationale

Wireless networking allows attackers within physical proximity to launch network-based attacks against systems, including those against local LAN protocols which were not designed with security in mind.

Disable Bluetooth Servicexccdf_org.ssgproject.content_rule_service_bluetooth_disabled medium

Disable Bluetooth Service

Rule IDxccdf_org.ssgproject.content_rule_service_bluetooth_disabled
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-17(8), AC-18(a), AC-18(d), AC-18(3), CM-7, 85, 1551

Description

The bluetooth service can be disabled with the following command:

$ sudo systemctl disable bluetooth.service
$ sudo service bluetooth stop

Rationale

Disabling the bluetooth service prevents the system from attempting connections to Bluetooth devices, which entails some security risk. Nevertheless, variation in this risk decision may be expected due to the utility of Bluetooth connectivity and its limited range.

Disable Bluetooth Kernel Modulesxccdf_org.ssgproject.content_rule_kernel_module_bluetooth_disabled medium

Disable Bluetooth Kernel Modules

Rule IDxccdf_org.ssgproject.content_rule_kernel_module_bluetooth_disabled
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-17(8), AC-18(a), AC-18(d), AC-18(3), CM-7, 85, 1551

Description

The kernel's module loading system can be configured to prevent loading of the Bluetooth module. Add the following to the appropriate /etc/modprobe.d configuration file to prevent the loading of the Bluetooth module:

install bluetooth /bin/true

Rationale

If Bluetooth functionality must be disabled, preventing the kernel from loading the kernel module provides an additional safeguard against its activation.

Disable IPv6 Networking Support Automatic Loadingxccdf_org.ssgproject.content_rule_sysctl_kernel_ipv6_disable medium

Disable IPv6 Networking Support Automatic Loading

Rule IDxccdf_org.ssgproject.content_rule_sysctl_kernel_ipv6_disable
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  CM-7, 1551

Description

To disable support for (ipv6) add the following line to /etc/sysctl.d/ipv6.conf (or another file in /etc/sysctl.d):

net.ipv6.conf.all.disable_ipv6 = 1
This disables IPv6 on all network interfaces as other services and system functionality require the IPv6 stack loaded to work.

Rationale

Any unnecessary network stacks - including IPv6 - should be disabled, to reduce the vulnerability to exploitation.

Disable Interface Usage of IPv6xccdf_org.ssgproject.content_rule_network_ipv6_disable_interfaces low

Disable Interface Usage of IPv6

Rule IDxccdf_org.ssgproject.content_rule_network_ipv6_disable_interfaces
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References
Description

To disable interface usage of IPv6, add or correct the following lines in /etc/sysconfig/network:

NETWORKING_IPV6=no
IPV6INIT=no

Disable Support for RPC IPv6xccdf_org.ssgproject.content_rule_network_ipv6_disable_rpc low

Disable Support for RPC IPv6

Rule IDxccdf_org.ssgproject.content_rule_network_ipv6_disable_rpc
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  CM-7

Description

RPC services for NFSv4 try to load transport modules for udp6 and tcp6 by default, even if IPv6 has been disabled in /etc/modprobe.d. To prevent RPC services such as rpc.mountd from attempting to start IPv6 network listeners, remove or comment out the following two lines in /etc/netconfig:

udp6       tpi_clts      v     inet6    udp     -       -
tcp6       tpi_cots_ord  v     inet6    tcp     -       -

Disable Accepting IPv6 Router Advertisementsxccdf_org.ssgproject.content_rule_sysctl_net_ipv6_conf_default_accept_ra low

Disable Accepting IPv6 Router Advertisements

Rule IDxccdf_org.ssgproject.content_rule_sysctl_net_ipv6_conf_default_accept_ra
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  CM-7

Description

To set the runtime status of the net.ipv6.conf.default.accept_ra kernel parameter, run the following command:

$ sudo sysctl -w net.ipv6.conf.default.accept_ra=0
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv6.conf.default.accept_ra = 0

Rationale

An illicit router advertisement message could result in a man-in-the-middle attack.

Disable Accepting IPv6 Redirectsxccdf_org.ssgproject.content_rule_sysctl_net_ipv6_conf_default_accept_redirects medium

Disable Accepting IPv6 Redirects

Rule IDxccdf_org.ssgproject.content_rule_sysctl_net_ipv6_conf_default_accept_redirects
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  CM-7, 1551

Description

To set the runtime status of the net.ipv6.conf.default.accept_redirects kernel parameter, run the following command:

$ sudo sysctl -w net.ipv6.conf.default.accept_redirects=0
If this is not the system's default value, add the following line to /etc/sysctl.conf:
net.ipv6.conf.default.accept_redirects = 0

Rationale

An illicit ICMP redirect message could result in a man-in-the-middle attack.

Manually Assign Global IPv6 Addressxccdf_org.ssgproject.content_rule_network_ipv6_static_address low

Manually Assign Global IPv6 Address

Rule IDxccdf_org.ssgproject.content_rule_network_ipv6_static_address
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  366

Description

To manually assign an IP address for an interface, edit the file /etc/sysconfig/network-scripts/ifcfg-interface. Add or correct the following line (substituting the correct IPv6 address):

IPV6ADDR=2001:0DB8::ABCD/64
Manually assigning an IP address is preferable to accepting one from routers or from the network otherwise. The example address here is an IPv6 address reserved for documentation purposes, as defined by RFC3849.

Use Privacy Extensions for Addressxccdf_org.ssgproject.content_rule_network_ipv6_privacy_extensions low

Use Privacy Extensions for Address

Rule IDxccdf_org.ssgproject.content_rule_network_ipv6_privacy_extensions
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  366

Description

To introduce randomness into the automatic generation of IPv6 addresses, add or correct the following line in /etc/sysconfig/network-scripts/ifcfg-interface:

IPV6_PRIVACY=rfc3041
Automatically-generated IPv6 addresses are based on the underlying hardware (e.g. Ethernet) address, and so it becomes possible to track a piece of hardware over its lifetime using its traffic. If it is important for a system's IP address to not trivially reveal its hardware address, this setting should be applied.

Manually Assign IPv6 Router Addressxccdf_org.ssgproject.content_rule_network_ipv6_default_gateway low

Manually Assign IPv6 Router Address

Rule IDxccdf_org.ssgproject.content_rule_network_ipv6_default_gateway
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  366

Description

Edit the file /etc/sysconfig/network-scripts/ifcfg-interface, and add or correct the following line (substituting your gateway IP as appropriate):

IPV6_DEFAULTGW=2001:0DB8::0001
Router addresses should be manually set and not accepted via any auto-configuration or router advertisement.

Verify firewalld Enabledxccdf_org.ssgproject.content_rule_service_firewalld_enabled medium

Verify firewalld Enabled

Rule IDxccdf_org.ssgproject.content_rule_service_firewalld_enabled
Result
pass
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References
Description

The firewalld service can be enabled with the following command:

$ sudo systemctl enable firewalld.service

Rationale

The dynamic firewall daemon firewalld provides a dynamically managed firewall with support for network “zones”, Ethernet bridges, and has a separation of runtime and permanent configuration options. It has support for both IPv4 and IPv6 firewall settings.

Set Default firewalld Zone for Incoming Packetsxccdf_org.ssgproject.content_rule_set_firewalld_default_zone medium

Set Default firewalld Zone for Incoming Packets

Rule IDxccdf_org.ssgproject.content_rule_set_firewalld_default_zone
Result
fail
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  CM-7, 66, 1109, 1154, 1414

Description

To set the default zone to drop for the built-in default zone which processes incoming IPv4 and IPv6 packets, modify the following line in /etc/firewalld/firewalld.conf to be:

DefaultZone=drop

Rationale

In firewalld the default zone is applied only after all the applicable rules in the table are examined for a match. Setting the default zone to drop implements proper design for a firewall, i.e. any packets which are not explicitly permitted should not be accepted.

Disable DCCP Supportxccdf_org.ssgproject.content_rule_kernel_module_dccp_disabled mediumCCE-26828-4

Disable DCCP Support

Rule IDxccdf_org.ssgproject.content_rule_kernel_module_dccp_disabled
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

identifiers:  CCE-26828-4

Description

The Datagram Congestion Control Protocol (DCCP) is a relatively new transport layer protocol, designed to support streaming media and telephony. To configure the system to prevent the dccp kernel module from being loaded, add the following line to a file in the directory /etc/modprobe.d:

install dccp /bin/true

Rationale

Disabling DCCP protects the system against exploitation of any flaws in its implementation.

Install libreswan Packagexccdf_org.ssgproject.content_rule_package_libreswan_installed medium

Install libreswan Package

Rule IDxccdf_org.ssgproject.content_rule_package_libreswan_installed
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-17, MA-4, SC-9, 1130, 1131, Req-4.1

Description

The Libreswan package provides an implementation of IPsec and IKE, which permits the creation of secure tunnels over untrusted networks. The libreswan package can be installed with the following command:

$ sudo dnf install libreswan

Rationale

Providing the ability for remote users or systems to initiate a secure VPN connection protects information when it is transmitted over a wide area network.

Verify Any Configured IPSec Tunnel Connectionsxccdf_org.ssgproject.content_rule_libreswan_approved_tunnels medium

Verify Any Configured IPSec Tunnel Connections

Rule IDxccdf_org.ssgproject.content_rule_libreswan_approved_tunnels
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-4, 336, SRG-OS-000480-GPOS-00227, 040830

Description

Libreswan provides an implementation of IPsec and IKE, which permits the creation of secure tunnels over untrusted networks. As such, IPsec can be used to circumvent certain network requirements such as filtering. Verify that if any IPsec connection (conn) configured in /etc/ipsec.conf and /etc/ipsec.d exists is an approved organizational connection.

Rationale

IP tunneling mechanisms can be used to bypass network filtering.

Disable Zeroconf Networkingxccdf_org.ssgproject.content_rule_network_disable_zeroconf low

Disable Zeroconf Networking

Rule IDxccdf_org.ssgproject.content_rule_network_disable_zeroconf
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  CM-7

Description

Zeroconf networking allows the system to assign itself an IP address and engage in IP communication without a statically-assigned address or even a DHCP server. Automatic address assignment via Zeroconf (or DHCP) is not recommended. To disable Zeroconf automatic route assignment in the 169.254.0.0 subnet, add or correct the following line in /etc/sysconfig/network:

NOZEROCONF=yes

Rationale

Zeroconf addresses are in the network 169.254.0.0. The networking scripts add entries to the system's routing table for these addresses. Zeroconf address assignment commonly occurs when the system is configured to use DHCP but fails to receive an address assignment from the DHCP server.

Ensure System is Not Acting as a Network Snifferxccdf_org.ssgproject.content_rule_network_sniffer_disabled low

Ensure System is Not Acting as a Network Sniffer

Rule IDxccdf_org.ssgproject.content_rule_network_sniffer_disabled
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  CM-7, MA-3

Description

The system should not be acting as a network sniffer, which can capture all traffic on the network to which it is connected. Run the following to determine if any interface is running in promiscuous mode:

$ ip link | grep PROMISC

Rationale

If any results are returned, then a sniffing process (such as tcpdump or Wireshark) is likely to be using the interface and this should be investigated.

Ensure Log Files Are Owned By Appropriate Userxccdf_org.ssgproject.content_rule_rsyslog_files_ownership medium

Ensure Log Files Are Owned By Appropriate User

Rule IDxccdf_org.ssgproject.content_rule_rsyslog_files_ownership
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-6, SI-11, 1314

Description

The owner of all log files written by rsyslog should be root. These log files are determined by the second part of each Rule line in /etc/rsyslog.conf and typically all appear in /var/log. For each log file LOGFILE referenced in /etc/rsyslog.conf, run the following command to inspect the file's owner:

$ ls -l LOGFILE
If the owner is not root, run the following command to correct this:
$ sudo chown root LOGFILE

Rationale

The log files generated by rsyslog contain valuable information regarding system configuration, user authentication, and other such information. Log files should be protected from unauthorized access.

Ensure Log Files Are Owned By Appropriate Groupxccdf_org.ssgproject.content_rule_rsyslog_files_groupownership medium

Ensure Log Files Are Owned By Appropriate Group

Rule IDxccdf_org.ssgproject.content_rule_rsyslog_files_groupownership
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-6, SI-11, 1314

Description

The group-owner of all log files written by rsyslog should be root. These log files are determined by the second part of each Rule line in /etc/rsyslog.conf and typically all appear in /var/log. For each log file LOGFILE referenced in /etc/rsyslog.conf, run the following command to inspect the file's group owner:

$ ls -l LOGFILE
If the owner is not root, run the following command to correct this:
$ sudo chgrp root LOGFILE

Rationale

The log files generated by rsyslog contain valuable information regarding system configuration, user authentication, and other such information. Log files should be protected from unauthorized access.

Ensure System Log Files Have Correct Permissionsxccdf_org.ssgproject.content_rule_rsyslog_files_permissions medium

Ensure System Log Files Have Correct Permissions

Rule IDxccdf_org.ssgproject.content_rule_rsyslog_files_permissions
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  SI-11, 1314

Description

The file permissions for all log files written by rsyslog should be set to 600, or more restrictive. These log files are determined by the second part of each Rule line in /etc/rsyslog.conf and typically all appear in /var/log. For each log file LOGFILE referenced in /etc/rsyslog.conf, run the following command to inspect the file's permissions:

$ ls -l LOGFILE
If the permissions are not 600 or more restrictive, run the following command to correct this:
$ sudo chmod 0600 LOGFILE

Rationale

Log files can contain valuable information regarding system configuration. If the system log files are not protected unauthorized users could change the logged data, eliminating their forensic value.

Ensure Logs Sent To Remote Hostxccdf_org.ssgproject.content_rule_rsyslog_send_messages_to_logserver low

Ensure Logs Sent To Remote Host

Rule IDxccdf_org.ssgproject.content_rule_rsyslog_send_messages_to_logserver
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AU-3(2), AU-9, 1348, 136

Description

To configure rsyslog to send logs to a remote log server, open /etc/rsyslog.conf and read and understand the last section of the file, which describes the multiple directives necessary to activate remote logging. Along with these other directives, the system can be configured to forward its logs to a particular log server by adding or correcting one of the following lines, substituting loghost.example.com appropriately. The choice of protocol depends on the environment of the system; although TCP and RELP provide more reliable message delivery, they may not be supported in all environments.
To use UDP for log message delivery:

*.* @loghost.example.com

To use TCP for log message delivery:
*.* @@loghost.example.com

To use RELP for log message delivery:
*.* :omrelp:loghost.example.com

Rationale

A log server (loghost) receives syslog messages from one or more systems. This data can be used as an additional log source in the event a system is compromised and its local logs are suspect. Forwarding log messages to a remote loghost also provides system administrators with a centralized place to view the status of multiple hosts within the enterprise.

Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Serverxccdf_org.ssgproject.content_rule_rsyslog_accept_remote_messages_none low

Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Server

Rule IDxccdf_org.ssgproject.content_rule_rsyslog_accept_remote_messages_none
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AU-9(2), AC-4

Description

The rsyslog daemon should not accept remote messages unless the system acts as a log server. To ensure that it is not listening on the network, ensure the following lines are not found in /etc/rsyslog.conf:

$ModLoad imtcp
$InputTCPServerRun port
$ModLoad imudp
$UDPServerRun port
$ModLoad imrelp
$InputRELPServerRun port

Rationale

Any process which receives messages from the network incurs some risk of receiving malicious messages. This risk can be eliminated for rsyslog by configuring it not to listen on the network.

Enable rsyslog to Accept Messages via TCP, if Acting As Log Serverxccdf_org.ssgproject.content_rule_rsyslog_accept_remote_messages_tcp low

Enable rsyslog to Accept Messages via TCP, if Acting As Log Server

Rule IDxccdf_org.ssgproject.content_rule_rsyslog_accept_remote_messages_tcp
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AU-9

Description

The rsyslog daemon should not accept remote messages unless the system acts as a log server. If the system needs to act as a central log server, add the following lines to /etc/rsyslog.conf to enable reception of messages over TCP:

$ModLoad imtcp
$InputTCPServerRun 514

Rationale

If the system needs to act as a log server, this ensures that it can receive messages over a reliable TCP connection.

Enable rsyslog to Accept Messages via UDP, if Acting As Log Serverxccdf_org.ssgproject.content_rule_rsyslog_accept_remote_messages_udp low

Enable rsyslog to Accept Messages via UDP, if Acting As Log Server

Rule IDxccdf_org.ssgproject.content_rule_rsyslog_accept_remote_messages_udp
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AU-9

Description

The rsyslog daemon should not accept remote messages unless the system acts as a log server. If the system needs to act as a central log server, add the following lines to /etc/rsyslog.conf to enable reception of messages over UDP:

$ModLoad imudp
$UDPServerRun 514

Rationale

Many devices, such as switches, routers, and other Unix-like systems, may only support the traditional syslog transmission over UDP. If the system must act as a log server, this enables it to receive their messages as well.

Ensure Logrotate Runs Periodicallyxccdf_org.ssgproject.content_rule_ensure_logrotate_activated low

Ensure Logrotate Runs Periodically

Rule IDxccdf_org.ssgproject.content_rule_ensure_logrotate_activated
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AU-9, 366

Description

The logrotate utility allows for the automatic rotation of log files. The frequency of rotation is specified in /etc/logrotate.conf, which triggers a cron task. To configure logrotate to run daily, add or correct the following line in /etc/logrotate.conf:

# rotate log files frequency
daily

Rationale

Log files that are not properly rotated run the risk of growing so large that they fill up the /var/log partition. Valuable logging information could be lost if the /var/log partition becomes full.

Configure Logwatch HostLimit Linexccdf_org.ssgproject.content_rule_configure_logwatch_hostlimit low

Configure Logwatch HostLimit Line

Rule IDxccdf_org.ssgproject.content_rule_configure_logwatch_hostlimit
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References
Description

On a central logserver, you want Logwatch to summarize all syslog entries, including those which did not originate on the logserver itself. The HostLimit setting tells Logwatch to report on all hosts, not just the one on which it is running.

 HostLimit = no 

Configure Logwatch SplitHosts Linexccdf_org.ssgproject.content_rule_configure_logwatch_splithosts low

Configure Logwatch SplitHosts Line

Rule IDxccdf_org.ssgproject.content_rule_configure_logwatch_splithosts
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References
Description

If SplitHosts is set, Logwatch will separate entries by hostname. This makes the report longer but significantly more usable. If it is not set, then Logwatch will not report which host generated a given log entry, and that information is almost always necessary

 SplitHosts = yes 

Ensure rsyslog is Installedxccdf_org.ssgproject.content_rule_package_rsyslog_installed medium

Ensure rsyslog is Installed

Rule IDxccdf_org.ssgproject.content_rule_package_rsyslog_installed
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AU-9(2), 1311, 1312

Description

Rsyslog is installed by default. The rsyslog package can be installed with the following command:

$ sudo dnf install rsyslog

Rationale

The rsyslog package provides the rsyslog daemon, which provides system logging services.

Enable rsyslog Servicexccdf_org.ssgproject.content_rule_service_rsyslog_enabled medium

Enable rsyslog Service

Rule IDxccdf_org.ssgproject.content_rule_service_rsyslog_enabled
Result
notselected
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AU-12, 1557, 1312, 1311

Description

The rsyslog service provides syslog-style logging by default on Fedora. The rsyslog service can be enabled with the following command:

$ sudo systemctl enable rsyslog.service

Rationale

The rsyslog service must be running in order to provide logging services, which are essential to system administration.

Disable Logwatch on Clients if a Logserver Existsxccdf_org.ssgproject.content_rule_disable_logwatch_for_logserver low

Disable Logwatch on Clients if a Logserver Exists

Rule IDxccdf_org.ssgproject.content_rule_disable_logwatch_for_logserver
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References
Description

Does your site have a central logserver which has been configured to report on logs received from all systems? If so:

 
$ sudo rm /etc/cron.daily/0logwatch 
If no logserver exists, it will be necessary for each machine to run Logwatch individually. Using a central logserver provides the security and reliability benefits discussed earlier, and also makes monitoring logs easier and less time-intensive for administrators.

Configure auditd Number of Logs Retainedxccdf_org.ssgproject.content_rule_auditd_data_retention_num_logs medium

Configure auditd Number of Logs Retained

Rule IDxccdf_org.ssgproject.content_rule_auditd_data_retention_num_logs
Result
fail
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AU-1(b), AU-11, IR-5

Description

Determine how many log files auditd should retain when it rotates logs. Edit the file /etc/audit/auditd.conf. Add or modify the following line, substituting NUMLOGS with the correct value of 5:

num_logs = NUMLOGS
Set the value to 5 for general-purpose systems. Note that values less than 2 result in no log rotation.

Rationale

The total storage for audit log files must be large enough to retain log information over the period required. This is a function of the maximum log file size and the number of logs retained.

Configure auditd Max Log File Sizexccdf_org.ssgproject.content_rule_auditd_data_retention_max_log_file medium

Configure auditd Max Log File Size

Rule IDxccdf_org.ssgproject.content_rule_auditd_data_retention_max_log_file
Result
fail
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AU-1(b), AU-11, IR-5

Description

Determine the amount of audit data (in megabytes) which should be retained in each log file. Edit the file /etc/audit/auditd.conf. Add or modify the following line, substituting the correct value of 6 for STOREMB:

max_log_file = STOREMB
Set the value to 6 (MB) or higher for general-purpose systems. Larger values, of course, support retention of even more audit data.

Rationale

The total storage for audit log files must be large enough to retain log information over the period required. This is a function of the maximum log file size and the number of logs retained.

Configure auditd max_log_file_action Upon Reaching Maximum Log Sizexccdf_org.ssgproject.content_rule_auditd_data_retention_max_log_file_action medium

Configure auditd max_log_file_action Upon Reaching Maximum Log Size

Rule IDxccdf_org.ssgproject.content_rule_auditd_data_retention_max_log_file_action
Result
fail
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AU-1(b), AU-4, AU-11, IR-5

Description

The default action to take when the logs reach their maximum size is to rotate the log files, discarding the oldest one. To configure the action taken by auditd, add or correct the line in /etc/audit/auditd.conf:

max_log_file_action = ACTION
Possible values for ACTION are described in the auditd.conf man page. These include:
  • ignore
  • syslog
  • suspend
  • rotate
  • keep_logs
Set the ACTION to rotate to ensure log rotation occurs. This is the default. The setting is case-insensitive.

Rationale

Automatically rotating logs (by setting this to rotate) minimizes the chances of the system unexpectedly running out of disk space by being overwhelmed with log data. However, for systems that must never discard log data, or which use external processes to transfer it and reclaim space, keep_logs can be employed.

Configure auditd space_left Action on Low Disk Spacexccdf_org.ssgproject.content_rule_auditd_data_retention_space_left_action medium

Configure auditd space_left Action on Low Disk Space

Rule IDxccdf_org.ssgproject.content_rule_auditd_data_retention_space_left_action
Result
fail
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AU-1(b), AU-4, AU-5(b), IR-5, 140, 143

Description

The auditd service can be configured to take an action when disk space starts to run low. Edit the file /etc/audit/auditd.conf. Modify the following line, substituting ACTION appropriately:

space_left_action = ACTION
Possible values for ACTION are described in the auditd.conf man page. These include:
  • ignore
  • syslog
  • email
  • exec
  • suspend
  • single
  • halt
Set this to email (instead of the default, which is suspend) as it is more likely to get prompt attention. Acceptable values also include suspend, single, and halt.

Rationale

Notifying administrators of an impending disk space problem may allow them to take corrective action prior to any disruption.

Configure auditd admin_space_left Action on Low Disk Spacexccdf_org.ssgproject.content_rule_auditd_data_retention_admin_space_left_action medium

Configure auditd admin_space_left Action on Low Disk Space

Rule IDxccdf_org.ssgproject.content_rule_auditd_data_retention_admin_space_left_action
Result
fail
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AU-1(b), AU-4, AU-5(b), IR-5, 140, 1343

Description

The auditd service can be configured to take an action when disk space is running low but prior to running out of space completely. Edit the file /etc/audit/auditd.conf. Add or modify the following line, substituting ACTION appropriately:

admin_space_left_action = ACTION
Set this value to single to cause the system to switch to single user mode for corrective action. Acceptable values also include suspend and halt. For certain systems, the need for availability outweighs the need to log all actions, and a different setting should be determined. Details regarding all possible values for ACTION are described in the auditd.conf man page.

Rationale

Administrators should be made aware of an inability to record audit records. If a separate partition or logical volume of adequate size is used, running low on space for audit records should never occur.

Configure auditd mail_acct Action on Low Disk Spacexccdf_org.ssgproject.content_rule_auditd_data_retention_action_mail_acct medium

Configure auditd mail_acct Action on Low Disk Space

Rule IDxccdf_org.ssgproject.content_rule_auditd_data_retention_action_mail_acct
Result
fail
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AU-1(b), AU-4, AU-5(a), IR-5, 139, 144

Description

The auditd service can be configured to send email to a designated account in certain situations. Add or correct the following line in /etc/audit/auditd.conf to ensure that administrators are notified via email for those situations:

action_mail_acct = root

Rationale

Email sent to the root account is typically aliased to the administrators of the system, who can take appropriate action.

Configure auditd flush priorityxccdf_org.ssgproject.content_rule_auditd_data_retention_flush low

Configure auditd flush priority

Rule IDxccdf_org.ssgproject.content_rule_auditd_data_retention_flush
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AU-9, AU-12(1), 1576

Description

The auditd service can be configured to synchronously write audit event data to disk. Add or correct the following line in /etc/audit/auditd.conf to ensure that audit event data is fully synchronized with the log files on the disk:

flush = data

Rationale

Audit data should be synchronously written to disk to ensure log integrity. These parameters assure that all audit event data is fully synchronized with the log files on the disk.

Configure auditd to use audispd's syslog pluginxccdf_org.ssgproject.content_rule_auditd_audispd_syslog_plugin_activated medium

Configure auditd to use audispd's syslog plugin

Rule IDxccdf_org.ssgproject.content_rule_auditd_audispd_syslog_plugin_activated
Result
fail
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AU-1(b), AU-3(2), IR-5, 136

Description

To configure the auditd service to use the syslog plug-in of the audispd audit event multiplexor, set the active line in /etc/audisp/plugins.d/syslog.conf to yes. Restart the auditd service:

$ sudo service auditd restart

Rationale

The auditd service does not include the ability to send audit records to a centralized server for management directly. It does, however, include a plug-in for audit event multiplexor (audispd) to pass audit records to the local syslog server

Record attempts to alter time through adjtimexxccdf_org.ssgproject.content_rule_audit_rules_time_adjtimex low

Record attempts to alter time through adjtimex

Rule IDxccdf_org.ssgproject.content_rule_audit_rules_time_adjtimex
Result
fail
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 1487, 169

Description

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup (the default), add the following line to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S adjtimex -k audit_time_rules
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S adjtimex -k audit_time_rules
If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup, add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S adjtimex -k audit_time_rules
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S adjtimex -k audit_time_rules
The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport. Multiple system calls can be defined on the same line to save space if desired, but is not required. See an example of multiple combined syscalls:
-a always,exit -F arch=b64 -S adjtimex -S settimeofday -k audit_time_rules

Rationale

Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.

Record attempts to alter time through settimeofdayxccdf_org.ssgproject.content_rule_audit_rules_time_settimeofday low

Record attempts to alter time through settimeofday

Rule IDxccdf_org.ssgproject.content_rule_audit_rules_time_settimeofday
Result
fail
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 1487, 169

Description

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup (the default), add the following line to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S settimeofday -k audit_time_rules
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S settimeofday -k audit_time_rules
If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup, add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S settimeofday -k audit_time_rules
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S settimeofday -k audit_time_rules
The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport. Multiple system calls can be defined on the same line to save space if desired, but is not required. See an example of multiple combined syscalls:
-a always,exit -F arch=b64 -S adjtimex -S settimeofday -k audit_time_rules

Rationale

Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.

Record Attempts to Alter Time Through stimexccdf_org.ssgproject.content_rule_audit_rules_time_stime low

Record Attempts to Alter Time Through stime

Rule IDxccdf_org.ssgproject.content_rule_audit_rules_time_stime
Result
fail
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 1487, 169

Description

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup (the default), add the following line to /etc/audit/audit.rules file for both 32 bit and 64 bit systems:

-a always,exit -F arch=b32 -S stime -k audit_time_rules
Since the 64 bit version of the "stime" system call is not defined in the audit lookup table, the corresponding "-F arch=b64" form of this rule is not expected to be defined on 64 bit systems (the aforementioned "-F arch=b32" stime rule form itself is sufficient for both 32 bit and 64 bit systems). If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup, add the following line to a file with suffix .rules in the directory /etc/audit/rules.d for both 32 bit and 64 bit systems:
-a always,exit -F arch=b32 -S stime -k audit_time_rules
Since the 64 bit version of the "stime" system call is not defined in the audit lookup table, the corresponding "-F arch=b64" form of this rule is not expected to be defined on 64 bit systems (the aforementioned "-F arch=b32" stime rule form itself is sufficient for both 32 bit and 64 bit systems). The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport. Multiple system calls can be defined on the same line to save space if desired, but is not required. See an example of multiple combined system calls:
-a always,exit -F arch=b64 -S adjtimex -S settimeofday -k audit_time_rules

Rationale

Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.

Record Attempts to Alter Time Through clock_settimexccdf_org.ssgproject.content_rule_audit_rules_time_clock_settime low

Record Attempts to Alter Time Through clock_settime

Rule IDxccdf_org.ssgproject.content_rule_audit_rules_time_clock_settime
Result
fail
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 1487, 169

Description

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup (the default), add the following line to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S clock_settime -F a0=0x0 -F key=time-change
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S clock_settime -F a0=0x0 -F key=time-change
If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup, add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S clock_settime -F a0=0x0 -F key=time-change
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S clock_settime -F a0=0x0 -F key=time-change
The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport. Multiple system calls can be defined on the same line to save space if desired, but is not required. See an example of multiple combined syscalls:
-a always,exit -F arch=b64 -S adjtimex -S settimeofday -k audit_time_rules

Rationale

Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.

Remediation Shell script:   (show)

Complexity:high
Disruption:medium
Strategy:restrict


# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	PATTERN="-a always,exit -F arch=$ARCH -S clock_settime -F a0=.* \(-F key=\|-k \).*"
	GROUP="clock_settime"
	FULL_RULE="-a always,exit -F arch=$ARCH -S clock_settime -F a0=0x0 -k time-change"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'

function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
        echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
        echo "Aborting."
        exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
        echo "Unknown audit rules loading tool: $1. Aborting."
        echo "Use either 'auditctl' or 'augenrules'!"
        exit 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
        files_to_inspect=("${files_to_inspect[@]}" '/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
        # Extract audit $key from audit rule so we can use it later
        key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)')
        # Check if particular audit rule is already defined
        IFS=$'\n' matches=($(sed -s -n -e "/${pattern}/!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules))
        # Reset IFS back to default
        unset $IFS
        for match in "${matches[@]}"
        do
                files_to_inspect=("${files_to_inspect[@]}" "${match}")
        done
        # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
        if [ ${#files_to_inspect[@]} -eq "0" ]
        then
                files_to_inspect="/etc/audit/rules.d/$key.rules"
                if [ ! -e "$files_to_inspect" ]
                then
                        touch "$files_to_inspect"
                        chmod 0640 "$files_to_inspect"
                fi
        fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do

        # Filter existing $audit_file rules' definitions to select those that:
        # * follow the rule pattern, and
        # * meet the hardware architecture requirement, and
        # * are current syscall group specific
        IFS=$'\n' existing_rules=($(sed -e "/${pattern}/!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file"))
        # Reset IFS back to default
        unset $IFS

        # Process rules found case-by-case
        for rule in "${existing_rules[@]}"
        do
                # Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
                if [ "${rule}" != "${full_rule}" ]
                then
                        # If so, isolate just '(-S \w)+' substring of that rule
                        rule_syscalls=$(echo $rule | grep -o -P '(-S \w+ )+')
                        # Check if list of '-S syscall' arguments of that rule is subset
                        # of '-S syscall' list of expected $full_rule
                        if grep -q -- "$rule_syscalls" <<< "$full_rule"
                        then
                                # Rule is covered (i.e. the list of -S syscalls for this rule is
                                # subset of -S syscalls of $full_rule => existing rule can be deleted
                                # Thus delete the rule from audit.rules & our array
                                sed -i -e "/$rule/d" "$audit_file"
                                existing_rules=("${existing_rules[@]//$rule/}")
                        else
                                # Rule isn't covered by $full_rule - it besides -S syscall arguments
                                # for this group contains also -S syscall arguments for other syscall
                                # group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
                                # since 'lchown' & 'fchownat' share 'chown' substring
                                # Therefore:
                                # * 1) delete the original rule from audit.rules
                                # (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
                                # * 2) delete the -S syscall arguments for this syscall group, but
                                # keep those not belonging to this syscall group
                                # (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
                                # * 3) append the modified (filtered) rule again into audit.rules
                                # if the same rule not already present
                                #
                                # 1) Delete the original rule
                                sed -i -e "/$rule/d" "$audit_file"
                                # 2) Delete syscalls for this group, but keep those from other groups
                                # Convert current rule syscall's string into array splitting by '-S' delimiter
                                IFS=$'-S' read -a rule_syscalls_as_array <<< "$rule_syscalls"
                                # Reset IFS back to default
                                unset $IFS
                                # Declare new empty string to hold '-S syscall' arguments from other groups
                                new_syscalls_for_rule=''
                                # Walk through existing '-S syscall' arguments
                                for syscall_arg in "${rule_syscalls_as_array[@]}"
                                do
                                        # Skip empty $syscall_arg values
                                        if [ "$syscall_arg" == '' ]
                                        then
                                                continue
                                        fi
                                        # If the '-S syscall' doesn't belong to current group add it to the new list
                                        # (together with adding '-S' delimiter back for each of such item found)
                                        if grep -q -v -- "$group" <<< "$syscall_arg"
                                        then
                                                new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
                                        fi
                                done
                                # Replace original '-S syscall' list with the new one for this rule
                                updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
                                # Squeeze repeated whitespace characters in rule definition (if any) into one
                                updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
                                # 3) Append the modified / filtered rule again into audit.rules
                                #    (but only in case it's not present yet to prevent duplicate definitions)
                                if ! grep -q -- "$updated_rule" "$audit_file"
                                then
                                        echo "$updated_rule" >> "$audit_file"
                                fi
                        fi
                else
                        # $audit_file already contains the expected rule form for this
                        # architecture & key => don't insert it second time
                        append_expected_rule=1
                fi
        done

        # We deleted all rules that were subset of the expected one for this arch & key.
        # Also isolated rules containing system calls not from this system calls group.
        # Now append the expected rule if it's not present in $audit_file yet
        if [[ ${append_expected_rule} -eq "0" ]]
        then
                echo "$full_rule" >> "$audit_file"
        fi
done

}

	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done
Record Attempts to Alter the localtime Filexccdf_org.ssgproject.content_rule_audit_rules_time_watch_localtime low

Record Attempts to Alter the localtime File

Rule IDxccdf_org.ssgproject.content_rule_audit_rules_time_watch_localtime
Result
fail
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(b), IR-5, 1487, 169

Description

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup (the default), add the following line to /etc/audit/audit.rules file:

-w /etc/localtime -p wa -k audit_time_rules
If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup, add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-w /etc/localtime -p wa -k audit_time_rules
The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport and should always be used.

Rationale

Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.

Record Events that Modify the System's Discretionary Access Controls - chmodxccdf_org.ssgproject.content_rule_audit_rules_dac_modification_chmod low

Record Events that Modify the System's Discretionary Access Controls - chmod

Rule IDxccdf_org.ssgproject.content_rule_audit_rules_dac_modification_chmod
Result
fail
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126

Description

At a minimum the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup (the default), add the following line to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S chmod -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chmod  -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup, add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S chmod -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chmod  -F auid>=1000 -F auid!=4294967295 -k perm_mod

Rationale

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Warnings
warning  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Record Events that Modify the System's Discretionary Access Controls - chownxccdf_org.ssgproject.content_rule_audit_rules_dac_modification_chown low

Record Events that Modify the System's Discretionary Access Controls - chown

Rule IDxccdf_org.ssgproject.content_rule_audit_rules_dac_modification_chown
Result
fail
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126

Description

At a minimum the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup (the default), add the following line to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S chown -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chown -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup, add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S chown -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chown -F auid>=1000 -F auid!=4294967295 -k perm_mod

Rationale

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Warnings
warning  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Record Events that Modify the System's Discretionary Access Controls - fchmodxccdf_org.ssgproject.content_rule_audit_rules_dac_modification_fchmod low

Record Events that Modify the System's Discretionary Access Controls - fchmod

Rule IDxccdf_org.ssgproject.content_rule_audit_rules_dac_modification_fchmod
Result
fail
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126

Description

At a minimum the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup (the default), add the following line to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S fchmod -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchmod -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup, add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S fchmod -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchmod -F auid>=1000 -F auid!=4294967295 -k perm_mod

Rationale

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Warnings
warning  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Record Events that Modify the System's Discretionary Access Controls - fchmodatxccdf_org.ssgproject.content_rule_audit_rules_dac_modification_fchmodat low

Record Events that Modify the System's Discretionary Access Controls - fchmodat

Rule IDxccdf_org.ssgproject.content_rule_audit_rules_dac_modification_fchmodat
Result
fail
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126

Description

At a minimum the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup (the default), add the following line to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S fchmodat -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchmodat -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup, add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S fchmodat -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchmodat -F auid>=1000 -F auid!=4294967295 -k perm_mod

Rationale

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Warnings
warning  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Record Events that Modify the System's Discretionary Access Controls - fchownxccdf_org.ssgproject.content_rule_audit_rules_dac_modification_fchown low

Record Events that Modify the System's Discretionary Access Controls - fchown

Rule IDxccdf_org.ssgproject.content_rule_audit_rules_dac_modification_fchown
Result
fail
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126

Description

At a minimum the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup (the default), add the following line to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S fchown -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchown -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup, add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S fchown -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchown -F auid>=1000 -F auid!=4294967295 -k perm_mod

Rationale

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Warnings
warning  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Record Events that Modify the System's Discretionary Access Controls - fchownatxccdf_org.ssgproject.content_rule_audit_rules_dac_modification_fchownat low

Record Events that Modify the System's Discretionary Access Controls - fchownat

Rule IDxccdf_org.ssgproject.content_rule_audit_rules_dac_modification_fchownat
Result
fail
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126

Description

At a minimum the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup (the default), add the following line to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S fchownat -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchownat -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup, add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S fchownat -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchownat -F auid>=1000 -F auid!=4294967295 -k perm_mod

Rationale

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Warnings
warning  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Record Events that Modify the System's Discretionary Access Controls - fremovexattrxccdf_org.ssgproject.content_rule_audit_rules_dac_modification_fremovexattr low

Record Events that Modify the System's Discretionary Access Controls - fremovexattr

Rule IDxccdf_org.ssgproject.content_rule_audit_rules_dac_modification_fremovexattr
Result
fail
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126

Description

At a minimum the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup (the default), add the following line to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S fremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup, add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S fremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod

Rationale

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Warnings
warning  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Record Events that Modify the System's Discretionary Access Controls - fsetxattrxccdf_org.ssgproject.content_rule_audit_rules_dac_modification_fsetxattr low

Record Events that Modify the System's Discretionary Access Controls - fsetxattr

Rule IDxccdf_org.ssgproject.content_rule_audit_rules_dac_modification_fsetxattr
Result
fail
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126

Description

At a minimum the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup (the default), add the following line to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S fsetxattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fsetxattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup, add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S fsetxattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fsetxattr -F auid>=1000 -F auid!=4294967295 -k perm_mod

Rationale

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Warnings
warning  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Record Events that Modify the System's Discretionary Access Controls - lchownxccdf_org.ssgproject.content_rule_audit_rules_dac_modification_lchown low

Record Events that Modify the System's Discretionary Access Controls - lchown

Rule IDxccdf_org.ssgproject.content_rule_audit_rules_dac_modification_lchown
Result
fail
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126

Description

At a minimum the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup (the default), add the following line to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S lchown -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lchown -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup, add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S lchown -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lchown -F auid>=1000 -F auid!=4294967295 -k perm_mod

Rationale

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Warnings
warning  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Record Events that Modify the System's Discretionary Access Controls - lremovexattrxccdf_org.ssgproject.content_rule_audit_rules_dac_modification_lremovexattr low

Record Events that Modify the System's Discretionary Access Controls - lremovexattr

Rule IDxccdf_org.ssgproject.content_rule_audit_rules_dac_modification_lremovexattr
Result
fail
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126

Description

At a minimum the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup (the default), add the following line to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S lremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup, add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S lremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lremovexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod

Rationale

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Warnings
warning  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Record Events that Modify the System's Discretionary Access Controls - lsetxattrxccdf_org.ssgproject.content_rule_audit_rules_dac_modification_lsetxattr low

Record Events that Modify the System's Discretionary Access Controls - lsetxattr

Rule IDxccdf_org.ssgproject.content_rule_audit_rules_dac_modification_lsetxattr
Result
fail
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126

Description

At a minimum the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup (the default), add the following line to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S lsetxattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lsetxattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup, add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S lsetxattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lsetxattr -F auid>=1000 -F auid!=4294967295 -k perm_mod

Rationale

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Warnings
warning  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Record Events that Modify the System's Discretionary Access Controls - removexattrxccdf_org.ssgproject.content_rule_audit_rules_dac_modification_removexattr low

Record Events that Modify the System's Discretionary Access Controls - removexattr

Rule IDxccdf_org.ssgproject.content_rule_audit_rules_dac_modification_removexattr
Result
fail
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126

Description

At a minimum the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup (the default), add the following line to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S removexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S removexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup, add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S removexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S removexattr -F auid>=1000 -F auid!=4294967295 -k perm_mod

Rationale

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Warnings
warning  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Record Events that Modify the System's Discretionary Access Controls - setxattrxccdf_org.ssgproject.content_rule_audit_rules_dac_modification_setxattr low

Record Events that Modify the System's Discretionary Access Controls - setxattr

Rule IDxccdf_org.ssgproject.content_rule_audit_rules_dac_modification_setxattr
Result
fail
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126

Description

At a minimum the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup (the default), add the following line to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S setxattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S setxattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup, add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S setxattr -F auid>=1000 -F auid!=4294967295 -k perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S setxattr -F auid>=1000 -F auid!=4294967295 -k perm_mod

Rationale

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Warnings
warning  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Record Events that Modify User/Group Informationxccdf_org.ssgproject.content_rule_audit_rules_usergroup_modification low

Record Events that Modify User/Group Information

Rule IDxccdf_org.ssgproject.content_rule_audit_rules_usergroup_modification
Result
fail
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-2(4), AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 18, 1403, 1404, 1405, 1684, 1683, 1685, 1686

Description

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup (the default), add the following lines to /etc/audit/audit.rules file, in order to capture events that modify account changes:

-w /etc/group -p wa -k audit_rules_usergroup_modification
-w /etc/passwd -p wa -k audit_rules_usergroup_modification
-w /etc/gshadow -p wa -k audit_rules_usergroup_modification
-w /etc/shadow -p wa -k audit_rules_usergroup_modification
-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification
If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup, add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d, in order to capture events that modify account changes:
-w /etc/group -p wa -k audit_rules_usergroup_modification
-w /etc/passwd -p wa -k audit_rules_usergroup_modification
-w /etc/gshadow -p wa -k audit_rules_usergroup_modification
-w /etc/shadow -p wa -k audit_rules_usergroup_modification
-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification

Rationale

In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications should be investigated for legitimacy.

Record Events that Modify the System's Network Environmentxccdf_org.ssgproject.content_rule_audit_rules_networkconfig_modification low

Record Events that Modify the System's Network Environment

Rule IDxccdf_org.ssgproject.content_rule_audit_rules_networkconfig_modification
Result
fail
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5

Description

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup (the default), add the following lines to /etc/audit/audit.rules file, setting ARCH to either b32 or b64 as appropriate for your system:

-a always,exit -F arch=ARCH -S sethostname -S setdomainname -k audit_rules_networkconfig_modification
-w /etc/issue -p wa -k audit_rules_networkconfig_modification
-w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
-w /etc/hosts -p wa -k audit_rules_networkconfig_modification
-w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification
If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup, add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d, setting ARCH to either b32 or b64 as appropriate for your system:
-a always,exit -F arch=ARCH -S sethostname -S setdomainname -k audit_rules_networkconfig_modification
-w /etc/issue -p wa -k audit_rules_networkconfig_modification
-w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
-w /etc/hosts -p wa -k audit_rules_networkconfig_modification
-w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification

Rationale

The network environment should not be modified by anything other than administrator action. Any change to network parameters should be audited.

System Audit Logs Must Have Mode 0640 or Less Permissivexccdf_org.ssgproject.content_rule_file_permissions_var_log_audit low

System Audit Logs Must Have Mode 0640 or Less Permissive

Rule IDxccdf_org.ssgproject.content_rule_file_permissions_var_log_audit
Result
notselected
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-6, AU-1(b), AU-9, IR-5, http://iase.disa.mil/stigs/cci/Pages/index.aspx

Description

Change the mode of the audit log files with the following command:

$ sudo chmod 0640 audit_file

Rationale

If users can write to audit logs, audit trails can be modified or destroyed.

System Audit Logs Must Be Owned By Rootxccdf_org.ssgproject.content_rule_file_ownership_var_log_audit low

System Audit Logs Must Be Owned By Root

Rule IDxccdf_org.ssgproject.content_rule_file_ownership_var_log_audit
Result
pass
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-6, AU-1(b), AU-9, IR-5, 166

Description

To properly set the owner of /var/log, run the command:

$ sudo chown root /var/log

Rationale

Failure to give ownership of the audit log files to root allows the designated owner, and unauthorized users, potential access to sensitive information.

Record Events that Modify the System's Mandatory Access Controlsxccdf_org.ssgproject.content_rule_audit_rules_mac_modification low

Record Events that Modify the System's Mandatory Access Controls

Rule IDxccdf_org.ssgproject.content_rule_audit_rules_mac_modification
Result
fail
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5

Description

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup (the default), add the following line to /etc/audit/audit.rules file:

-w /etc/selinux/ -p wa -k MAC-policy
If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup, add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-w /etc/selinux/ -p wa -k MAC-policy

Rationale

The system's mandatory access policy (SELinux) should not be arbitrarily changed by anything other than administrator action. All changes to MAC policy should be audited.

Record Attempts to Alter Process and Session Initiation Informationxccdf_org.ssgproject.content_rule_audit_rules_session_events low

Record Attempts to Alter Process and Session Initiation Information

Rule IDxccdf_org.ssgproject.content_rule_audit_rules_session_events
Result
fail
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5

Description

The audit system already collects process information for all users and root. If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup (the default), add the following lines to /etc/audit/audit.rules file in order to watch for attempted manual edits of files involved in storing such process information:

-w /var/run/utmp -p wa -k session
-w /var/log/btmp -p wa -k session
-w /var/log/wtmp -p wa -k session
If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup, add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d in order to watch for attempted manual edits of files involved in storing such process information:
-w /var/run/utmp -p wa -k session
-w /var/log/btmp -p wa -k session
-w /var/log/wtmp -p wa -k session

Rationale

Manual editing of these files may indicate nefarious activity, such as an attacker attempting to remove evidence of an intrusion.

Ensure auditd Collects Unauthorized Access Attempts to Files (unsuccessful)xccdf_org.ssgproject.content_rule_audit_rules_unsuccessful_file_modification low

Ensure auditd Collects Unauthorized Access Attempts to Files (unsuccessful)

Rule IDxccdf_org.ssgproject.content_rule_audit_rules_unsuccessful_file_modification
Result
fail
Time2017-03-14T13:48:36
Severitylow
Identifiers and References

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126

Description

At a minimum the audit system should collect unauthorized file accesses for all users and root. If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup (the default), add the following lines to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=4294967295 -k access
-a always,exit -F arch=b32 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=4294967295 -k access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=4294967295 -k access
-a always,exit -F arch=b64 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=4294967295 -k access
If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup, add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=4294967295 -k access
-a always,exit -F arch=b32 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=4294967295 -k access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=4294967295 -k access
-a always,exit -F arch=b64 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=4294967295 -k access

Rationale

Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.

Ensure auditd Collects Information on the Use of Privileged Commandsxccdf_org.ssgproject.content_rule_audit_rules_privileged_commands low

Ensure auditd Collects Information on the Use of Privileged Commands

Rule IDxccdf_org.ssgproject.content_rule_audit_rules_privileged_commands
Result
fail
Time2017-03-14T13:49:23
Severitylow
Identifiers and References

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-2(4), AU-12(a), AU-12(c), IR-5, 40

Description

At a minimum the audit system should collect the execution of privileged commands for all users and root. To find the relevant setuid / setgid programs, run the following command for each local partition PART:

$ sudo find PART -xdev -type f -perm -4000 -o -type f -perm -2000 2>/dev/null
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup (the default), add a line of the following form to /etc/audit/audit.rules for each setuid / setgid program on the system, replacing the SETUID_PROG_PATH part with the full path of that setuid / setgid program in the list:
-a always,exit -F path=SETUID_PROG_PATH -F perm=x -F auid>=1000 -F auid!=4294967295 -k privileged
If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup, add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d for each setuid / setgid program on the system, replacing the SETUID_PROG_PATH part with the full path of that setuid / setgid program in the list:
-a always,exit -F path=SETUID_PROG_PATH -F perm=x -F auid>=1000 -F auid!=4294967295 -k privileged

Rationale

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Ensure auditd Collects Information on Exporting to Media (successful)xccdf_org.ssgproject.content_rule_audit_rules_media_export low

Ensure auditd Collects Information on Exporting to Media (successful)

Rule IDxccdf_org.ssgproject.content_rule_audit_rules_media_export
Result
fail
Time2017-03-14T13:49:23
Severitylow
Identifiers and References

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126

Description

At a minimum the audit system should collect media exportation events for all users and root. If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup (the default), add the following line to /etc/audit/audit.rules file, setting ARCH to either b32 or b64 as appropriate for your system:

-a always,exit -F arch=ARCH -S mount -F auid>=1000 -F auid!=4294967295 -k export
If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup, add the following line to a file with suffix .rules in the directory /etc/audit/rules.d, setting ARCH to either b32 or b64 as appropriate for your system:
-a always,exit -F arch=ARCH -S mount -F auid>=1000 -F auid!=4294967295 -k export

Rationale

The unauthorized exportation of data to external media could result in an information leak where classified information, Privacy Act information, and intellectual property could be lost. An audit trail should be created each time a filesystem is mounted to help identify and guard against information loss.

Ensure auditd Collects File Deletion Events by Userxccdf_org.ssgproject.content_rule_audit_rules_file_deletion_events low

Ensure auditd Collects File Deletion Events by User

Rule IDxccdf_org.ssgproject.content_rule_audit_rules_file_deletion_events
Result
fail
Time2017-03-14T13:49:23
Severitylow
Identifiers and References

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126

Description

At a minimum the audit system should collect file deletion events for all users and root. If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup (the default), add the following line to /etc/audit/audit.rules file, setting ARCH to either b32 or b64 as appropriate for your system:

-a always,exit -F arch=ARCH -S rmdir -S unlink -S unlinkat -S rename -S renameat -F auid>=1000 -F auid!=4294967295 -k delete
If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup, add the following line to a file with suffix .rules in the directory /etc/audit/rules.d, setting ARCH to either b32 or b64 as appropriate for your system:
-a always,exit -F arch=ARCH -S rmdir -S unlink -S unlinkat -S rename -S renameat -F auid>=1000 -F auid!=4294967295 -k delete

Rationale

Auditing file deletions will create an audit trail for files that are removed from the system. The audit trail could aid in system troubleshooting, as well as, detecting malicious processes that attempt to delete log files to conceal their presence.

Ensure auditd Collects System Administrator Actionsxccdf_org.ssgproject.content_rule_audit_rules_sysadmin_actions low

Ensure auditd Collects System Administrator Actions

Rule IDxccdf_org.ssgproject.content_rule_audit_rules_sysadmin_actions
Result
fail
Time2017-03-14T13:49:23
Severitylow
Identifiers and References

references:  AC-2(7)(b), AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126

Description

At a minimum the audit system should collect administrator actions for all users and root. If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup (the default), add the following line to /etc/audit/audit.rules file:

-w /etc/sudoers -p wa -k actions
If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup, add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-w /etc/sudoers -p wa -k actions

Rationale

The actions taken by system administrators should be audited to keep a record of what was executed on the system, as well as, for accountability purposes.

Ensure auditd Collects Information on Kernel Module Loading and Unloadingxccdf_org.ssgproject.content_rule_audit_rules_kernel_module_loading low

Ensure auditd Collects Information on Kernel Module Loading and Unloading

Rule IDxccdf_org.ssgproject.content_rule_audit_rules_kernel_module_loading
Result
fail
Time2017-03-14T13:49:23
Severitylow
Identifiers and References

references:  AC-17(7), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-12(a), AU-12(c), IR-5, 126

Description

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup (the default), add the following lines to /etc/audit/audit.rules file in order to capture kernel module loading and unloading events, setting ARCH to either b32 or b64 as appropriate for your system:

-w /usr/sbin/insmod -p x -k modules
-w /usr/sbin/rmmod -p x -k modules
-w /usr/sbin/modprobe -p x -k modules
-a always,exit -F arch=ARCH -S init_module -S delete_module -k modules
If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup, add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d to capture kernel module loading and unloading events, setting ARCH to either b32 or b64 as appropriate for your system:
-w /usr/sbin/insmod -p x -k modules
-w /usr/sbin/rmmod -p x -k modules
-w /usr/sbin/modprobe -p x -k modules
-a always,exit -F arch=ARCH -S init_module -S delete_module -k modules

Rationale

The addition/removal of kernel modules can be used to alter the behavior of the kernel and potentially introduce malicious code into kernel space. It is important to have an audit trail of modules that have been introduced into the kernel.

Make the auditd Configuration Immutablexccdf_org.ssgproject.content_rule_audit_rules_immutable low

Make the auditd Configuration Immutable

Rule IDxccdf_org.ssgproject.content_rule_audit_rules_immutable
Result
fail
Time2017-03-14T13:49:23
Severitylow
Identifiers and References

references:  AC-6, AU-1(b), AU-2(a), AU-2(c), AU-2(d), IR-5

Description

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup (the default), add the following line to /etc/audit/audit.rules file in order to make the auditd configuration immutable:

-e 2
If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup, add the following line to a file with suffix .rules in the directory /etc/audit/rules.d in order to make the auditd configuration immutable:
-e 2
With this setting, a reboot will be required to change any audit rules.

Rationale

Making the audit configuration immutable prevents accidental as well as malicious modification of the audit rules, although it may be problematic if legitimate changes are needed during system operation

Remediation Shell script:   (show)

Complexity:high
Disruption:medium
Strategy:restrict

# Traverse all of:
#
# /etc/audit/audit.rules,			(for auditctl case)
# /etc/audit/rules.d/*.rules			(for augenrules case)
#
# files to check if '-e .*' setting is present in that '*.rules' file already.
# If found, delete such occurrence since auditctl(8) manual page instructs the
# '-e 2' rule should be placed as the last rule in the configuration
find /etc/audit /etc/audit/rules.d -maxdepth 1 -type f -name *.rules -exec sed -i '/-e[[:space:]]\+.*/d' {} ';'

# Append '-e 2' requirement at the end of both:
# * /etc/audit/audit.rules file 		(for auditctl case)
# * /etc/audit/rules.d/immutable.rules		(for augenrules case)

for AUDIT_FILE in "/etc/audit/audit.rules" "/etc/audit/rules.d/immutable.rules"
do
	echo '' >> $AUDIT_FILE
	echo '# Set the audit.rules configuration immutable per security requirements' >> $AUDIT_FILE
	echo '# Reboot is required to change audit rules once this setting is applied' >> $AUDIT_FILE
	echo '-e 2' >> $AUDIT_FILE
done
Enable Auditing for Processes Which Start Prior to the Audit Daemonxccdf_org.ssgproject.content_rule_bootloader_audit_argument medium

Enable Auditing for Processes Which Start Prior to the Audit Daemon

Rule IDxccdf_org.ssgproject.content_rule_bootloader_audit_argument
Result
fail
Time2017-03-14T13:48:36
Severitymedium
Identifiers and References

references:  AC-17(1), AU-14(1), AU-1(b), AU-2(a), AU-2(c), AU-2(d), AU-10, IR-5, 1464, 130

Description

To ensure all processes can be audited, even those which start prior to the audit daemon, add the argument audit=1 to the default GRUB 2 command line for the Linux operating system in /etc/default/grub, in the manner below:

GRUB_CMDLINE_LINUX="rd.lvm.lv=fedora/swap rd.lvm.lv=fedora/root rd.luks.uuid=luks-3431fd4f-80aa-436e-8acf-24f5bcb4e23a rhgb quiet audit=1"

Rationale

Each process on the system carries an "auditable" flag which indicates whether its activities can be audited. Although auditd takes care of enabling this for all processes which launch after it does, adding the kernel argument ensures it is set for every process during boot.

Warnings
warning  The GRUB 2 configuration file, grub.cfg, is automatically updated each time a new kernel is installed. Note that any changes to /etc/default/grub require rebuilding the grub.cfg file. To update the GRUB 2 configuration file manually, use the
grub2-mkconfig -o
command as follows:
  • On BIOS-based machines, issue the following command as root:
    ~]# grub2-mkconfig -o /boot/grub2/grub.cfg
  • On UEFI-based machines, issue the following command as root:
    ~]# grub2-mkconfig -o /boot/efi/fedora/grub2/grub.cfg
Enable cron Servicexccdf_org.ssgproject.content_rule_service_crond_enabled medium

Enable cron Service

Rule IDxccdf_org.ssgproject.content_rule_service_crond_enabled
Result
notselected
Time2017-03-14T13:49:23
Severitymedium
Identifiers and References

references:  CM-7

Description

The crond service is used to execute commands at preconfigured times. It is required by almost all systems to perform necessary maintenance tasks, such as notifying root of system activity. The crond service can be enabled with the following command:

$ sudo systemctl enable crond.service

Rationale

Due to its usage for maintenance and security-supporting tasks, enabling the cron daemon is essential.

Disable anacron Servicexccdf_org.ssgproject.content_rule_disable_anacron low

Disable anacron Service

Rule IDxccdf_org.ssgproject.content_rule_disable_anacron
Result
notselected
Time2017-03-14T13:49:23
Severitylow
Identifiers and References

references:  CM-7

Description

The cronie-anacron package, which provides anacron functionality, is installed by default. The cronie-anacron package can be removed with the following command:

$ sudo dnf erase cronie-anacron

Rationale

The anacron service provides cron functionality for systems such as laptops and workstations that may be shut down during the normal times that cron jobs are scheduled to run. On systems which do not require this additional functionality, anacron could needlessly increase the possible attack surface for an intruder.

Disable At Service (atd)xccdf_org.ssgproject.content_rule_service_atd_disabled low

Disable At Service (atd)

Rule IDxccdf_org.ssgproject.content_rule_service_atd_disabled
Result
notselected
Time2017-03-14T13:49:23
Severitylow
Identifiers and References

references:  CM-7, 381

Description

The at and batch commands can be used to schedule tasks that are meant to be executed only once. This allows delayed execution in a manner similar to cron, except that it is not recurring. The daemon atd keeps track of tasks scheduled via at and batch, and executes them at the specified time. The atd service can be disabled with the following command:

$ sudo systemctl disable atd.service

Rationale

The atd service could be used by an unsophisticated insider to carry out activities outside of a normal login session, which could complicate accountability. Furthermore, the need to schedule tasks with at or batch is not common.

SSH Access via Empty Passwords Disabledxccdf_org.ssgproject.content_rule_sshd_disable_empty_passwords high

SSH Access via Empty Passwords Disabled

Rule IDxccdf_org.ssgproject.content_rule_sshd_disable_empty_passwords
Result
pass
Time2017-03-14T13:49:23
Severityhigh
Identifiers and References

references:  765, 766

Description

To explicitly disallow remote login from accounts with empty passwords, add or correct the following line in /etc/ssh/sshd_config:

PermitEmptyPasswords no
Any accounts with empty passwords should be disabled immediately, and PAM configuration should prevent users from being able to assign themselves empty passwords.

Rationale

Configuring this setting for the SSH daemon provides additional assurance that remote login via SSH will require a password, even in the event of misconfiguration elsewhere.

SSH Idle Timeout Interval Usedxccdf_org.ssgproject.content_rule_sshd_set_idle_timeout low

SSH Idle Timeout Interval Used

Rule IDxccdf_org.ssgproject.content_rule_sshd_set_idle_timeout
Result
pass
Time2017-03-14T13:49:23
Severitylow
Identifiers and References

references:  879, 1133

Description

SSH allows administrators to set an idle timeout interval. After this interval has passed, the idle user will be automatically logged out.

To set an idle timeout interval, edit the /etc/ssh/sshd_config file, locate the following line:

ClientAliveInterval INTERVAL
and correct it to have the form of:
ClientAliveInterval 300
The timeout INTERVAL is given in seconds. To have a timeout of 15 minutes, set INTERVAL to 900.

If a shorter timeout has already been set for the login shell, that value will preempt any SSH setting made here. Keep in mind that some processes may stop SSH from correctly detecting that the user is idle.

Rationale

Causing idle users to be automatically logged out guards against compromises one system leading trivially to compromises on another.

SSH Client Alive Count Usedxccdf_org.ssgproject.content_rule_sshd_set_keepalive low

SSH Client Alive Count Used

Rule IDxccdf_org.ssgproject.content_rule_sshd_set_keepalive
Result
pass
Time2017-03-14T13:49:23
Severitylow
Identifiers and References

references:  879, 1133

Description

To ensure the SSH idle timeout occurs precisely when the ClientAliveCountMax is set, edit /etc/ssh/sshd_config as follows:

ClientAliveCountMax 0

Rationale

This ensures a user login will be terminated as soon as the ClientAliveCountMax is reached.

Enable the Chrony Daemonxccdf_org.ssgproject.content_rule_service_chronyd_enabled medium

Enable the Chrony Daemon

Rule IDxccdf_org.ssgproject.content_rule_service_chronyd_enabled
Result
pass
Time2017-03-14T13:49:23
Severitymedium
Identifiers and References

references:  AU-8(1), 160

Description

The ntpd service can be enabled with the following command:

$ sudo systemctl enable ntpd.service

Rationale

Enabling the chronyd service ensures that the chronyd service will be running and that the system will synchronize its time to any servers specified. This is important whether the system is configured to be a client (and synchronize only its own clock) or it is also acting as an NTP server to other systems. Synchronizing time is essential for authentication services such as Kerberos, but it is also important for maintaining accurate logs and auditing possible security breaches.

The chrony daemon offers all of the functionality of ntpdate, which is now deprecated. Additional information on this is available at http://support.ntp.org/bin/view/Dev/DeprecatingNtpdate

Specify a Remote NTP Serverxccdf_org.ssgproject.content_rule_chronyd_specify_remote_server medium

Specify a Remote NTP Server

Rule IDxccdf_org.ssgproject.content_rule_chronyd_specify_remote_server
Result
fail
Time2017-03-14T13:49:23
Severitymedium
Identifiers and References

references:  AU-8(1), 160

Description

To specify a remote NTP server for time synchronization, edit the file /etc/chrony.conf. Add or correct the following lines, substituting the IP or hostname of a remote NTP server for ntpserver:

server ntpserver
This instructs the NTP software to contact that remote server to obtain time data.

Rationale

Synchronizing with an NTP server makes it possible to collate system logs from multiple sources or correlate computer events with real time events.

Specify Additional Remote NTP Serversxccdf_org.ssgproject.content_rule_chronyd_specify_multiple_servers low

Specify Additional Remote NTP Servers

Rule IDxccdf_org.ssgproject.content_rule_chronyd_specify_multiple_servers
Result
notselected
Time2017-03-14T13:49:23
Severitylow
Identifiers and References

references:  AU-8(1)

Description

Additional NTP servers can be specified for time synchronization in the file /etc/chrony.conf. To do so, add additional lines of the following form, substituting the IP address or hostname of a remote NTP server for ntpserver:

server ntpserver

Rationale

Specifying additional NTP servers increases the availability of accurate time data, in the event that one of the specified servers becomes unavailable. This is typical for a system acting as an NTP server for other systems.

Enable the Audit Daemonxccdf_org.ssgproject.content_rule_service_auditd_enabled medium

Enable the Audit Daemon

Rule IDxccdf_org.ssgproject.content_rule_service_auditd_enabled
Result
pass
Time2017-03-14T13:49:23
Severitymedium
Identifiers and References

references:  AU-8(1), 160

Description

The audit service can be enabled with the following command:

$ sudo systemctl enable audit.service

Rationale

Enabling the auditd service ensures that The Linux Audit system is capable to watch the system and generate log entries.

Disable vsftpd Servicexccdf_org.ssgproject.content_rule_disable_vsftpd low

Disable vsftpd Service

Rule IDxccdf_org.ssgproject.content_rule_disable_vsftpd
Result
notselected
Time2017-03-14T13:49:23
Severitylow
Identifiers and References

references:  CM-7, 1436

Description

The vsftpd service can be disabled with the following command:

$ sudo systemctl disable vsftpd.service

Rationale

Running FTP server software provides a network-based avenue of attack, and should be disabled if not needed. Furthermore, the FTP protocol is unencrypted and creates a risk of compromising sensitive information.

Uninstall vsftpd Packagexccdf_org.ssgproject.content_rule_uninstall_vsftpd low

Uninstall vsftpd Package

Rule IDxccdf_org.ssgproject.content_rule_uninstall_vsftpd
Result
notselected
Time2017-03-14T13:49:23
Severitylow
Identifiers and References

references:  CM-7, 1436

Description

The vsftpd package can be removed with the following command:

$ sudo dnf erase vsftpd

Rationale

Removing the vsftpd package decreases the risk of its accidental activation.

Install vsftpd Packagexccdf_org.ssgproject.content_rule_package_vsftpd_installed low

Install vsftpd Package

Rule IDxccdf_org.ssgproject.content_rule_package_vsftpd_installed
Result
notselected
Time2017-03-14T13:49:23
Severitylow
Identifiers and References

references:  CM-7

Description

If this machine must operate as an FTP server, install the vsftpd package via the standard channels.

$ sudo dnf install vsftpd

Rationale

After Red Hat Enterprise Linux 2.1, Red Hat switched from distributing wu-ftpd with Red Hat Enterprise Linux to distributing vsftpd. For security and for consistency with future Red Hat releases, the use of vsftpd is recommended.

Restrict Access to Anonymous Users if Possiblexccdf_org.ssgproject.content_rule_ftp_restrict_to_anon low

Restrict Access to Anonymous Users if Possible

Rule IDxccdf_org.ssgproject.content_rule_ftp_restrict_to_anon
Result
notselected
Time2017-03-14T13:49:23
Severitylow
Identifiers and References
Description

Is there a mission-critical reason for users to transfer files to/from their own accounts using FTP, rather than using a secure protocol like SCP/SFTP? If not, edit the vsftpd configuration file. Add or correct the following configuration option:

local_enable=NO
If non-anonymous FTP logins are necessary, follow the guidance in the remainder of this section to secure these logins as much as possible.

Rationale

The use of non-anonymous FTP logins is strongly discouraged. Since SSH clients and servers are widely available, and since SSH provides support for a transfer mode which resembles FTP in user interface, there is no good reason to allow password-based FTP access.

Enable Logging of All FTP Transactionsxccdf_org.ssgproject.content_rule_ftp_log_transactions low

Enable Logging of All FTP Transactions

Rule IDxccdf_org.ssgproject.content_rule_ftp_log_transactions
Result
notselected
Time2017-03-14T13:49:23
Severitylow
Identifiers and References
Description

Add or correct the following configuration options within the vsftpd configuration file, located at /etc/vsftpd/vsftpd.conf:

xferlog_enable=YES
xferlog_std_format=NO
log_ftp_protocol=YES

Rationale

To trace malicious activity facilitated by the FTP service, it must be configured to ensure that all commands sent to the FTP server are logged using the verbose vsftpd log format. The default vsftpd log file is /var/log/vsftpd.log.

Warnings
warning  If verbose logging to vsftpd.log is done, sparse logging of downloads to /var/log/xferlog will not also occur. However, the information about what files were downloaded is included in the information logged to vsftpd.log
Create Warning Banners for All FTP Usersxccdf_org.ssgproject.content_rule_ftp_present_banner medium

Create Warning Banners for All FTP Users

Rule IDxccdf_org.ssgproject.content_rule_ftp_present_banner
Result
notselected
Time2017-03-14T13:49:23
Severitymedium
Identifiers and References

references:  48

Description

Edit the vsftpd configuration file, which resides at /etc/vsftpd/vsftpd.conf by default. Add or correct the following configuration options:

banner_file=/etc/issue

Rationale

This setting will cause the system greeting banner to be used for FTP connections as well.

Disable FTP Uploads if Possiblexccdf_org.ssgproject.content_rule_ftp_disable_uploads low

Disable FTP Uploads if Possible

Rule IDxccdf_org.ssgproject.content_rule_ftp_disable_uploads
Result
notselected
Time2017-03-14T13:49:23
Severitylow
Identifiers and References
Description

Is there a mission-critical reason for users to upload files via FTP? If not, edit the vsftpd configuration file to add or correct the following configuration options:

write_enable=NO
If FTP uploads are necessary, follow the guidance in the remainder of this section to secure these transactions as much as possible.

Rationale

Anonymous FTP can be a convenient way to make files available for universal download. However, it is less common to have a need to allow unauthenticated users to place files on the FTP server. If this must be done, it is necessary to ensure that files cannot be uploaded and downloaded from the same directory.

Place the FTP Home Directory on its Own Partitionxccdf_org.ssgproject.content_rule_ftp_home_partition low

Place the FTP Home Directory on its Own Partition

Rule IDxccdf_org.ssgproject.content_rule_ftp_home_partition
Result
notselected
Time2017-03-14T13:49:23
Severitylow
Identifiers and References
Description

By default, the anonymous FTP root is the home directory of the FTP user account. The df command can be used to verify that this directory is on its own partition.

Rationale

If there is a mission-critical reason for anonymous users to upload files, precautions must be taken to prevent these users from filling a disk used by other services.

Disable snmpd Servicexccdf_org.ssgproject.content_rule_disable_snmpd low

Disable snmpd Service

Rule IDxccdf_org.ssgproject.content_rule_disable_snmpd
Result
notselected
Time2017-03-14T13:49:23
Severitylow
Identifiers and References
Description

The snmpd service can be disabled with the following command:

$ sudo systemctl disable snmpd.service

Rationale

Running SNMP software provides a network-based avenue of attack, and should be disabled if not needed.

Uninstall net-snmp Packagexccdf_org.ssgproject.content_rule_package_net-snmp_removed low

Uninstall net-snmp Package

Rule IDxccdf_org.ssgproject.content_rule_package_net-snmp_removed
Result
notselected
Time2017-03-14T13:49:23
Severitylow
Identifiers and References
Description

The net-snmp package provides the snmpd service. The net-snmp package can be removed with the following command:

$ sudo dnf erase net-snmp

Rationale

If there is no need to run SNMP server software, removing the package provides a safeguard against its activation.

Configure SNMP Service to Use Only SNMPv3 or Newer xccdf_org.ssgproject.content_rule_snmpd_use_newer_protocol medium

Configure SNMP Service to Use Only SNMPv3 or Newer

Rule IDxccdf_org.ssgproject.content_rule_snmpd_use_newer_protocol
Result
notselected
Time2017-03-14T13:49:23
Severitymedium
Identifiers and References
Description

Edit /etc/snmp/snmpd.conf, removing any references to rocommunity, rwcommunity, or com2sec. Upon doing that, restart the SNMP service:

# service snmpd restart

Rationale

Earlier versions of SNMP are considered insecure, as they potentially allow unauthorized access to detailed system management information.

Ensure Default Password Is Not Usedxccdf_org.ssgproject.content_rule_snmpd_not_default_password medium

Ensure Default Password Is Not Used

Rule IDxccdf_org.ssgproject.content_rule_snmpd_not_default_password
Result
notselected
Time2017-03-14T13:49:23
Severitymedium
Identifiers and References
Description

Edit /etc/snmp/snmpd.conf, remove default community string public. Upon doing that, restart the SNMP service:

# service snmpd restart

Rationale

Presence of the default SNMP password enables querying of different system aspects and could result in unauthorized knowledge of the system.

Disable Network File System Lock Service (nfslock)xccdf_org.ssgproject.content_rule_service_nfslock_disabled low

Disable Network File System Lock Service (nfslock)

Rule IDxccdf_org.ssgproject.content_rule_service_nfslock_disabled
Result
notselected
Time2017-03-14T13:49:23
Severitylow
Identifiers and References
Description

The Network File System Lock (nfslock) service starts the required remote procedure call (RPC) processes which allow clients to lock files on the server. If the local machine is not configured to mount NFS filesystems then this service should be disabled. The nfslock service can be disabled with the following command:

$ sudo systemctl disable nfslock.service

Disable Secure RPC Client Service (rpcgssd)xccdf_org.ssgproject.content_rule_service_rpcgssd_disabled low

Disable Secure RPC Client Service (rpcgssd)

Rule IDxccdf_org.ssgproject.content_rule_service_rpcgssd_disabled
Result
notselected
Time2017-03-14T13:49:23
Severitylow
Identifiers and References
Description

The rpcgssd service manages RPCSEC GSS contexts required to secure protocols that use RPC (most often Kerberos and NFS). The rpcgssd service is the client-side of RPCSEC GSS. If the system does not require secure RPC then this service should be disabled. The rpcgssd service can be disabled with the following command:

$ sudo systemctl disable rpcgssd.service

Disable RPC ID Mapping Service (rpcidmapd)xccdf_org.ssgproject.content_rule_service_rpcidmapd_disabled low

Disable RPC ID Mapping Service (rpcidmapd)

Rule IDxccdf_org.ssgproject.content_rule_service_rpcidmapd_disabled
Result
notselected
Time2017-03-14T13:49:23
Severitylow
Identifiers and References
Description

The rpcidmapd service is used to map user names and groups to UID and GID numbers on NFSv4 mounts. If NFS is not in use on the local system then this service should be disabled. The rpcidmapd service can be disabled with the following command:

$ sudo systemctl disable rpcidmapd.service

Disable Network File Systems (netfs)xccdf_org.ssgproject.content_rule_service_netfs_disabled low

Disable Network File Systems (netfs)

Rule IDxccdf_org.ssgproject.content_rule_service_netfs_disabled
Result
notselected
Time2017-03-14T13:49:23
Severitylow
Identifiers and References
Description

The netfs script manages the boot-time mounting of several types of networked filesystems, of which NFS and Samba are the most common. If these filesystem types are not in use, the script can be disabled, protecting the system somewhat against accidental or malicious changes to /etc/fstab and against flaws in the netfs script itself. The netfs service can be disabled with the following command:

$ sudo systemctl disable netfs.service

Configure lockd to use static TCP portxccdf_org.ssgproject.content_rule_nfs_fixed_lockd_tcp_port low

Configure lockd to use static TCP port

Rule IDxccdf_org.ssgproject.content_rule_nfs_fixed_lockd_tcp_port
Result
notselected
Time2017-03-14T13:49:23
Severitylow
Identifiers and References
Description

Configure the lockd daemon to use a static TCP port as opposed to letting the RPC Bind service dynamically assign a port. Edit the file /etc/sysconfig/nfs. Add or correct the following line:

LOCKD_TCPPORT=lockd-port
Where lockd-port is a port which is not used by any other service on your network.

Rationale

Restrict service to always use a given port, so that firewalling can be done effectively.

Configure lockd to use static UDP portxccdf_org.ssgproject.content_rule_nfs_fixed_lockd_udp_port low

Configure lockd to use static UDP port

Rule IDxccdf_org.ssgproject.content_rule_nfs_fixed_lockd_udp_port
Result
notselected
Time2017-03-14T13:49:23
Severitylow
Identifiers and References
Description

Configure the lockd daemon to use a static UDP port as opposed to letting the RPC Bind service dynamically assign a port. Edit the file /etc/sysconfig/nfs. Add or correct the following line:

LOCKD_UDPPORT=lockd-port
Where lockd-port is a port which is not used by any other service on your network.

Rationale

Restricting services to always use a given port enables firewalling to be done more effectively.

Configure statd to use static portxccdf_org.ssgproject.content_rule_nfs_fixed_statd_port low

Configure statd to use static port

Rule IDxccdf_org.ssgproject.content_rule_nfs_fixed_statd_port
Result
notselected
Time2017-03-14T13:49:23
Severitylow
Identifiers and References
Description

Configure the statd daemon to use a static port as opposed to letting the RPC Bind service dynamically assign a port. Edit the file /etc/sysconfig/nfs. Add or correct the following line:

STATD_PORT=statd-port
Where statd-port is a port which is not used by any other service on your network.

Rationale

Restricting services to always use a given port enables firewalling to be done more effectively.

Configure mountd to use static portxccdf_org.ssgproject.content_rule_nfs_fixed_mountd_port low

Configure mountd to use static port

Rule IDxccdf_org.ssgproject.content_rule_nfs_fixed_mountd_port
Result
notselected
Time2017-03-14T13:49:23
Severitylow
Identifiers and References
Description

Configure the mountd daemon to use a static port as opposed to letting the RPC Bind service dynamically assign a port. Edit the file /etc/sysconfig/nfs. Add or correct the following line:

MOUNTD_PORT=statd-port
Where mountd-port is a port which is not used by any other service on your network.

Rationale

Restricting services to always use a given port enables firewalling to be done more effectively.

Specify UID and GID for Anonymous NFS Connectionsxccdf_org.ssgproject.content_rule_nfs_no_anonymous low

Specify UID and GID for Anonymous NFS Connections

Rule IDxccdf_org.ssgproject.content_rule_nfs_no_anonymous
Result
notselected
Time2017-03-14T13:49:23
Severitylow
Identifiers and References
Description

To specify the UID and GID for remote root users, edit the /etc/exports file and add the following for each export:

anonuid=-1
anongid=-1

Rationale

Specifying the anonymous UID and GID as -1 ensures that the remote root user is mapped to a local account which has no permissions on the system.

Disable Network File System (nfs)xccdf_org.ssgproject.content_rule_service_nfs_disabled low

Disable Network File System (nfs)

Rule IDxccdf_org.ssgproject.content_rule_service_nfs_disabled
Result
notselected
Time2017-03-14T13:49:23
Severitylow
Identifiers and References
Description

The Network File System (NFS) service allows remote hosts to mount and interact with shared filesystems on the local machine. If the local machine is not designated as a NFS server then this service should be disabled. The nfs service can be disabled with the following command:

$ sudo systemctl disable nfs.service

Rationale

Unnecessary services should be disabled to decrease the attack surface of the system.

Disable Secure RPC Server Service (rpcsvcgssd)xccdf_org.ssgproject.content_rule_service_rpcsvcgssd_disabled low

Disable Secure RPC Server Service (rpcsvcgssd)

Rule IDxccdf_org.ssgproject.content_rule_service_rpcsvcgssd_disabled
Result
notselected
Time2017-03-14T13:49:23
Severitylow
Identifiers and References
Description

The rpcsvcgssd service manages RPCSEC GSS contexts required to secure protocols that use RPC (most often Kerberos and NFS). The rpcsvcgssd service is the server-side of RPCSEC GSS. If the system does not require secure RPC then this service should be disabled. The rpcsvcgssd service can be disabled with the following command:

$ sudo systemctl disable rpcsvcgssd.service

Rationale

Unnecessary services should be disabled to decrease the attack surface of the system.

Mount Remote Filesystems with nodevxccdf_org.ssgproject.content_rule_use_nodev_option_on_nfs_mounts medium

Mount Remote Filesystems with nodev

Rule IDxccdf_org.ssgproject.content_rule_use_nodev_option_on_nfs_mounts
Result
notselected
Time2017-03-14T13:49:23
Severitymedium
Identifiers and References
Description

Add the nodev option to the fourth column of /etc/fstab for the line which controls mounting of any NFS mounts.

Rationale

Legitimate device files should only exist in the /dev directory. NFS mounts should not present device files to users.

Mount Remote Filesystems with nosuidxccdf_org.ssgproject.content_rule_use_nosuid_option_on_nfs_mounts medium

Mount Remote Filesystems with nosuid

Rule IDxccdf_org.ssgproject.content_rule_use_nosuid_option_on_nfs_mounts
Result
notselected
Time2017-03-14T13:49:23
Severitymedium
Identifiers and References
Description

Add the nosuid option to the fourth column of /etc/fstab for the line which controls mounting of any NFS mounts.

Rationale

NFS mounts should not present suid binaries to users. Only vendor-supplied suid executables should be installed to their default location on the local filesystem.

Use Root-Squashing on All Exportsxccdf_org.ssgproject.content_rule_use_root_squashing_all_exports low

Use Root-Squashing on All Exports

Rule IDxccdf_org.ssgproject.content_rule_use_root_squashing_all_exports
Result
notselected
Time2017-03-14T13:49:23
Severitylow
Identifiers and References
Description

If a filesystem is exported using root squashing, requests from root on the client are considered to be unprivileged (mapped to a user such as nobody). This provides some mild protection against remote abuse of an NFS server. Root squashing is enabled by default, and should not be disabled.

Ensure that no line in /etc/exports contains the option no_root_squash.

Rationale

If the NFS server allows root access to local file systems from remote hosts, this access could be used to compromise the system.

Restrict NFS Clients to Privileged Portsxccdf_org.ssgproject.content_rule_restrict_nfs_clients_to_privileged_ports low

Restrict NFS Clients to Privileged Ports

Rule IDxccdf_org.ssgproject.content_rule_restrict_nfs_clients_to_privileged_ports
Result
notselected
Time2017-03-14T13:49:23
Severitylow
Identifiers and References
Description

By default, the server NFS implementation requires that all client requests be made from ports less than 1024. If your organization has control over machines connected to its network, and if NFS requests are prohibited at the border firewall, this offers some protection against malicious requests from unprivileged users. Therefore, the default should not be changed.

To ensure that the default has not been changed, ensure no line in /etc/exports contains the option insecure.

Rationale

Allowing client requests to be made from ports higher than 1024 could allow a unprivileged user to initiate an NFS connection. If the unprivileged user account has been compromised, an attacker could gain access to data on the NFS server.

Ensure Insecure File Locking is Not Allowedxccdf_org.ssgproject.content_rule_no_insecure_locks_exports medium

Ensure Insecure File Locking is Not Allowed

Rule IDxccdf_org.ssgproject.content_rule_no_insecure_locks_exports
Result
notselected
Time2017-03-14T13:49:23
Severitymedium
Identifiers and References

references:  764

Description

By default the NFS server requires secure file-lock requests, which require credentials from the client in order to lock a file. Most NFS clients send credentials with file lock requests, however, there are a few clients that do not send credentials when requesting a file-lock, allowing the client to only be able to lock world-readable files. To get around this, the insecure_locks option can be used so these clients can access the desired export. This poses a security risk by potentially allowing the client access to data for which it does not have authorization. Remove any instances of the insecure_locks option from the file /etc/exports.

Rationale

Allowing insecure file locking could allow for sensitive data to be viewed or edited by an unauthorized user.

Disable X Windows Startup By Setting Default Targetxccdf_org.ssgproject.content_rule_xwindows_runlevel_setting low

Disable X Windows Startup By Setting Default Target

Rule IDxccdf_org.ssgproject.content_rule_xwindows_runlevel_setting
Result
notselected
Time2017-03-14T13:49:23
Severitylow
Identifiers and References

references:  AC-3, 366

Description

Setting the system's default target to multi-user will prevent automatic startup of the X server. To do so, run:

$ systemctl set-default multi-user.target
You should see the following output:
rm '/etc/systemd/system/default.target'
ln -s '/usr/lib/systemd/system/multi-user.target' '/etc/systemd/system/default.target'

Rationale

Unnecessary services should be disabled to decrease the attack surface of the system.

Remove the X Windows Package Groupxccdf_org.ssgproject.content_rule_package_xorg-x11-server-common_removed low

Remove the X Windows Package Group

Rule IDxccdf_org.ssgproject.content_rule_package_xorg-x11-server-common_removed
Result
notselected
Time2017-03-14T13:49:23
Severitylow
Identifiers and References

references:  366, 3.2

Description

Removing all packages which constitute the X Window System ensures users or malicious software cannot start X. To do so, run the following command:

$ sudo dnf groupremove "X Window System"

Rationale

Unnecessary packages should not be installed to decrease the attack surface of the system.

Red Hat and Red Hat Enterprise Linux are either registered trademarks or trademarks of Red Hat, Inc. in the United States and other countries. All other names are registered trademarks or trademarks of their respective companies.