Guide to the Secure Configuration of Red Hat Enterprise Linux 6

with profile Example Server Profile
This profile is an example of a customized server profile.
This guide presents a catalog of security-relevant configuration settings for Red Hat Enterprise Linux 6. 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, 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.

Profile Information

Profile TitleExample Server Profile
Profile IDxccdf_org.ssgproject.content_profile_CS2

CPE Platforms

  • cpe:/o:redhat:enterprise_linux:6
  • cpe:/o:redhat:enterprise_linux:6::client
  • cpe:/o:redhat:enterprise_linux:6::computenode

Revision History

Current version: 0.1.43

  • draft (as of 2019-02-21)

Table of Contents

  1. Services
    1. Obsolete Services
    2. FTP Server
    3. SNMP Server
    4. Cron and At Daemons
    5. X Window System
    6. DNS Server
    7. LDAP
    8. Mail Server Software
    9. Samba(SMB) Microsoft Windows File Sharing Server
    10. Web Server
    11. Network Time Protocol
    12. Base Services
    13. Proxy Server
    14. DHCP
    15. IMAP and POP3 Server
    16. NFS and RPC
    17. Print Support
    18. Avahi Server
    19. SSH Server
  2. System Settings
    1. Installing and Maintaining Software
    2. Configure Syslog
    3. Network Configuration and Firewalls
    4. SELinux
    5. Set Boot Loader Password
    6. Account and Access Control
    7. System Accounting with auditd
    8. File Permissions and Masks

Checklist

Group   Guide to the Secure Configuration of Red Hat Enterprise Linux 6   Group contains 134 groups and 313 rules
Group   Services   Group contains 63 groups and 124 rules

[ref]   The best protection against vulnerable software is running less software. This section describes how to review the software which Red Hat Enterprise Linux 6 installs on a system and disable software which is not needed. It then enumerates the software packages installed on a default Red Hat Enterprise Linux 6 system and provides guidance about which ones can be safely disabled.

Red Hat Enterprise Linux 6 provides a convenient minimal install option that essentially installs the bare necessities for a functional system. When building Red Hat Enterprise Linux 6 systems, it is highly recommended to select the minimal packages and then build up the system from there.

Group   Obsolete Services   Group contains 5 groups and 12 rules

[ref]   This section discusses a number of network-visible services which have historically caused problems for system security, and for which disabling or severely limiting the service has been the best available guidance for some time. As a result of this, many of these services are not installed as part of Red Hat Enterprise Linux 6 by default.

Organizations which are running these services should switch to more secure equivalents as soon as possible. If it remains absolutely necessary to run one of these services for legacy reasons, care should be taken to restrict the service as much as possible, for instance by configuring host firewall software such as iptables to restrict access to the vulnerable service to only those remote hosts which have a known need to use it.

Group   Rlogin, Rsh, and Rexec   Group contains 3 rules

[ref]   The Berkeley r-commands are legacy services which allow cleartext remote access and have an insecure trust model.

Rule   Disable rsh Service   [ref]

The rsh service, which is available with the rsh-server package and runs as a service through xinetd or separately as a systemd socket, should be disabled. If using xinetd, set disable to yes in /etc/xinetd.d/rsh.

Rationale:

The rsh service uses unencrypted network communications, which means that data from the login session, including passwords and all other information transmitted during the session, can be stolen by eavesdroppers on the network.

Severity: 
high
Identifiers and References

Identifiers:  CCE-26994-4

References:  RHEL-06-000214, SV-50395r2_rule, SRG-OS-000033, 2.2.17, 1, 11, 12, 14, 15, 16, 3, 5, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.06, DSS06.10, 3.1.13, 3.4.7, CCI-000068, CCI-001436, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.18.1.4, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, AC-17(8), CM-7, IA-5(1)(c), PR.AC-1, PR.AC-3, PR.AC-6, PR.AC-7, PR.IP-1, PR.PT-3, PR.PT-4

Rule   Uninstall rsh-server Package   [ref]

The rsh-server package can be removed with the following command:

$ sudo yum erase rsh-server

Rationale:

The rsh-server service provides unencrypted remote access service which does not provide for the confidentiality and integrity of user passwords or the remote session and has very weak authentication. If a privileged user were to login using this service, the privileged user password could be compromised. The rsh-server package provides several obsolete and insecure network services. Removing it decreases the risk of those services' accidental (or intentional) activation.

Severity: 
high
Identifiers and References

Identifiers:  CCE-27062-9

References:  CCI-000305, RHEL-06-000213, SV-50392r1_rule, CM-7, SRG-OS-000095, PR.IP-1, PR.PT-3, 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-000381, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, AC-17(8), CM-7(a), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000095-GPOS-00049

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:disable
# Function to remove packages on RHEL, Fedora, Debian, and possibly other systems.
#
# Example Call(s):
#
#     package_remove telnet-server
#
function package_remove {

# Load function arguments into local variables
local package="$1"

# Check sanity of the input
if [ $# -ne "1" ]
then
  echo "Usage: package_remove 'package_name'"
  echo "Aborting."
  exit 1
fi

if which dnf ; then
  if rpm -q --quiet "$package"; then
    dnf remove -y "$package"
  fi
elif which yum ; then
  if rpm -q --quiet "$package"; then
    yum remove -y "$package"
  fi
elif which apt-get ; then
  apt-get remove -y "$package"
else
  echo "Failed to detect available packaging system, tried dnf, yum and apt-get!"
  echo "Aborting."
  exit 1
fi

}

package_remove rsh-server
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Ensure rsh-server is removed
  package:
    name: rsh-server
    state: absent
  tags:
    - package_rsh-server_removed
    - high_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-27062-9
    - NIST-800-53-CM-7
    - NIST-800-53-AC-17(8)
    - NIST-800-53-CM-7(a)
    - DISA-STIG-RHEL-06-000213
  
Remediation Puppet snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
include remove_rsh-server

class remove_rsh-server {
  package { 'rsh-server':
    ensure => 'purged',
  }
}
Remediation Anaconda snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable

package --remove=rsh-server

Rule   Remove Rsh Trust Files   [ref]

The files /etc/hosts.equiv and ~/.rhosts (in each user's home directory) list remote hosts and users that are trusted by the local system when using the rshd daemon. To remove these files, run the following command to delete them from any location:

$ sudo rm /etc/hosts.equiv
$ rm ~/.rhosts

Rationale:

Trust files are convenient, but when used in conjunction with the R-services, they can allow unauthenticated access to a system.

Severity: 
high
Identifiers and References

Identifiers:  CCE-27270-8

References:  RHEL-06-000019, SV-50292r1_rule, SRG-OS-000248, 6.2.14, 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-001436, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, AC-17(8), CM-7, PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4

Remediation Shell script:   (show)

find /home -maxdepth 2 -type f -name .rhosts -exec rm -f '{}' \;

if [ -f /etc/hosts.equiv ]; then
	/bin/rm -f /etc/hosts.equiv
fi
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:restrict
- block:
    - name: "Detect shosts.equiv Files on the System"
      find:
          paths: /
          recurse: yes
          patterns: shosts.equiv
      check_mode: no
      register: shosts_equiv_locations

    - name: "Remove Rsh Trust Files"
      file:
          path: "{{ item.path }}"
          state: absent
      with_items: "{{ shosts_equiv_locations.files }}"
      when: shosts_equiv_locations and True
  tags:
    - no_rsh_trust_files
    - high_severity
    - restrict_strategy
    - low_complexity
    - low_disruption
    - CCE-27270-8
    - NIST-800-53-AC-17(8)
    - NIST-800-53-CM-7
    - DISA-STIG-RHEL-06-000019
Group   Telnet   Group contains 2 rules

[ref]   The telnet protocol does not provide confidentiality or integrity for information transmitted on the network. This includes authentication information such as passwords. Organizations which use telnet should be actively working to migrate to a more secure protocol.

Rule   Disable telnet Service   [ref]

The telnet service configuration file /etc/xinetd.d/telnet is not created automatically. If it was created manually, check the /etc/xinetd.d/telnet file and ensure that disable = no is changed to read disable = yes as follows below:

# description: The telnet server serves telnet sessions; it uses \\
#       unencrypted username/password pairs for authentication.
service telnet
{
        flags           = REUSE
        socket_type     = stream

        wait            = no
        user            = root
        server          = /usr/sbin/in.telnetd
        log_on_failure  += USERID
        disable         = yes
}
If the /etc/xinetd.d/telnet file does not exist, make sure that the activation of the telnet service on system boot is disabled via the following command:

Rationale:

The telnet protocol uses unencrypted network communication, which means that data from the login session, including passwords and all other information transmitted during the session, can be stolen by eavesdroppers on the network. The telnet protocol is also subject to man-in-the-middle attacks.

Severity: 
high
Identifiers and References

Identifiers:  CCE-26836-7

References:  CCI-000068, CCI-001436, CCI-000197, CCI-000877, CCI-000888, RHEL-06-000211, SV-50390r2_rule, SRG-OS-000129, 2.2.18, 1, 11, 12, 14, 15, 16, 3, 5, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.06, DSS06.10, 3.1.13, 3.4.7, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.18.1.4, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, AC-17(8), CM-7, IA-5(1)(c), PR.AC-1, PR.AC-3, PR.AC-6, PR.AC-7, PR.IP-1, PR.PT-3, PR.PT-4

Rule   Uninstall telnet-server Package   [ref]

The telnet-server package can be removed with the following command:

$ sudo yum erase telnet-server

Rationale:

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities are often overlooked and therefore may remain unsecure. They increase the risk to the platform by providing additional attack vectors.
The telnet service provides an unencrypted remote access service which does not provide for the confidentiality and integrity of user passwords or the remote session. If a privileged user were to login using this service, the privileged user password could be compromised.
Removing the telnet-server package decreases the risk of the telnet service's accidental (or intentional) activation.

Severity: 
high
Identifiers and References

Identifiers:  CCE-27073-6

References:  CCI-000305, RHEL-06-000206, SV-50388r1_rule, CM-7, SRG-OS-000095, PR.IP-1, PR.PT-3, 2.1.1, 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-000381, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, AC-17(8), CM-7(a), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000095-GPOS-00049

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:disable
# Function to remove packages on RHEL, Fedora, Debian, and possibly other systems.
#
# Example Call(s):
#
#     package_remove telnet-server
#
function package_remove {

# Load function arguments into local variables
local package="$1"

# Check sanity of the input
if [ $# -ne "1" ]
then
  echo "Usage: package_remove 'package_name'"
  echo "Aborting."
  exit 1
fi

if which dnf ; then
  if rpm -q --quiet "$package"; then
    dnf remove -y "$package"
  fi
elif which yum ; then
  if rpm -q --quiet "$package"; then
    yum remove -y "$package"
  fi
elif which apt-get ; then
  apt-get remove -y "$package"
else
  echo "Failed to detect available packaging system, tried dnf, yum and apt-get!"
  echo "Aborting."
  exit 1
fi

}

package_remove telnet-server
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Ensure telnet-server is removed
  package:
    name: telnet-server
    state: absent
  tags:
    - package_telnet-server_removed
    - high_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-27073-6
    - NIST-800-53-CM-7
    - NIST-800-53-AC-17(8)
    - NIST-800-53-CM-7(a)
    - DISA-STIG-RHEL-06-000206
  
Remediation Puppet snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
include remove_telnet-server

class remove_telnet-server {
  package { 'telnet-server':
    ensure => 'purged',
  }
}
Remediation Anaconda snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable

package --remove=telnet-server
Group   NIS   Group contains 2 rules

[ref]   The Network Information Service (NIS), also known as 'Yellow Pages' (YP), and its successor NIS+ have been made obsolete by Kerberos, LDAP, and other modern centralized authentication services. NIS should not be used because it suffers from security problems inherent in its design, such as inadequate protection of important authentication information.

Rule   Disable ypbind Service   [ref]

The ypbind service, which allows the system to act as a client in a NIS or NIS+ domain, should be disabled. The ypbind service can be disabled with the following command:

$ sudo chkconfig ypbind off

Rationale:

Disabling the ypbind service ensures the system is not acting as a client in a NIS or NIS+ domain. This service should be disabled unless in use.

Severity: 
medium
Identifiers and References

Identifiers:  CCE-26894-6

References:  RHEL-06-000221, SV-50405r2_rule, SRG-OS-000096, 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-000305, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, AC-17(8), CM-7, PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'ypbind' disable
/sbin/chkconfig --level 0123456 'ypbind' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service ypbind
  service:
    name: ypbind
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_ypbind_disabled
    - medium_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-26894-6
    - NIST-800-53-AC-17(8)
    - NIST-800-53-CM-7
    - DISA-STIG-RHEL-06-000221
  

Rule   Uninstall ypserv Package   [ref]

The ypserv package can be removed with the following command:

$ sudo yum erase ypserv

Rationale:

The NIS service provides an unencrypted authentication service which does not provide for the confidentiality and integrity of user passwords or the remote session. Removing the ypserv package decreases the risk of the accidental (or intentional) activation of NIS or NIS+ services.

Severity: 
high
Identifiers and References

Identifiers:  CCE-27079-3

References:  CCI-000305, RHEL-06-000220, SV-50404r1_rule, CM-7, SRG-OS-000095, PR.IP-1, PR.PT-3, 2.2.16, 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-000381, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, AC-17(8), CM-7(a), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000095-GPOS-00049

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:disable
# Function to remove packages on RHEL, Fedora, Debian, and possibly other systems.
#
# Example Call(s):
#
#     package_remove telnet-server
#
function package_remove {

# Load function arguments into local variables
local package="$1"

# Check sanity of the input
if [ $# -ne "1" ]
then
  echo "Usage: package_remove 'package_name'"
  echo "Aborting."
  exit 1
fi

if which dnf ; then
  if rpm -q --quiet "$package"; then
    dnf remove -y "$package"
  fi
elif which yum ; then
  if rpm -q --quiet "$package"; then
    yum remove -y "$package"
  fi
elif which apt-get ; then
  apt-get remove -y "$package"
else
  echo "Failed to detect available packaging system, tried dnf, yum and apt-get!"
  echo "Aborting."
  exit 1
fi

}

package_remove ypserv
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Ensure ypserv is removed
  package:
    name: ypserv
    state: absent
  tags:
    - package_ypserv_removed
    - high_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-27079-3
    - NIST-800-53-CM-7
    - NIST-800-53-AC-17(8)
    - NIST-800-53-CM-7(a)
    - DISA-STIG-RHEL-06-000220
  
Remediation Puppet snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
include remove_ypserv

class remove_ypserv {
  package { 'ypserv':
    ensure => 'purged',
  }
}
Remediation Anaconda snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable

package --remove=ypserv
Group   TFTP Server   Group contains 3 rules

[ref]   TFTP is a lightweight version of the FTP protocol which has traditionally been used to configure networking equipment. However, TFTP provides little security, and modern versions of networking operating systems frequently support configuration via SSH or other more secure protocols. A TFTP server should be run only if no more secure method of supporting existing equipment can be found.

Rule   Disable tftp Service   [ref]

The tftp service should be disabled. The tftp service can be disabled with the following command:

$ sudo chkconfig tftp off

Rationale:

Disabling the tftp service ensures the system is not acting as a TFTP server, which does not provide encryption or authentication.

Severity: 
medium
Identifiers and References

Identifiers:  CCE-27055-3

References:  RHEL-06-000223, SV-50410r2_rule, SRG-OS-000248, 2.1.6, 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-001436, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, AC-17(8), CM-7, PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'tftp' disable
/sbin/chkconfig --level 0123456 'tftp' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service tftp
  service:
    name: tftp
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_tftp_disabled
    - medium_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-27055-3
    - NIST-800-53-AC-17(8)
    - NIST-800-53-CM-7
    - DISA-STIG-RHEL-06-000223
  

Rule   Uninstall tftp-server Package   [ref]

The tftp-server package can be removed with the following command:

 $ sudo yum erase tftp-server

Rationale:

Removing the tftp-server package decreases the risk of the accidental (or intentional) activation of tftp services.

If TFTP is required for operational support (such as transmission of router configurations), its use must be documented with the Information Systems Securty Manager (ISSM), restricted to only authorized personnel, and have access control rules established.

Severity: 
high
Identifiers and References

Identifiers:  CCE-26946-4

References:  CCI-000305, RHEL-06-000222, SV-50407r3_rule, SRG-OS-000095, 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-000318, CCI-000368, CCI-001812, CCI-001813, CCI-001814, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, AC-17(8), CM-6(c), CM-7, PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000480-GPOS-00227

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:disable
# Function to remove packages on RHEL, Fedora, Debian, and possibly other systems.
#
# Example Call(s):
#
#     package_remove telnet-server
#
function package_remove {

# Load function arguments into local variables
local package="$1"

# Check sanity of the input
if [ $# -ne "1" ]
then
  echo "Usage: package_remove 'package_name'"
  echo "Aborting."
  exit 1
fi

if which dnf ; then
  if rpm -q --quiet "$package"; then
    dnf remove -y "$package"
  fi
elif which yum ; then
  if rpm -q --quiet "$package"; then
    yum remove -y "$package"
  fi
elif which apt-get ; then
  apt-get remove -y "$package"
else
  echo "Failed to detect available packaging system, tried dnf, yum and apt-get!"
  echo "Aborting."
  exit 1
fi

}

package_remove tftp-server
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Ensure tftp-server is removed
  package:
    name: tftp-server
    state: absent
  tags:
    - package_tftp-server_removed
    - high_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-26946-4
    - NIST-800-53-AC-17(8)
    - NIST-800-53-CM-6(c)
    - NIST-800-53-CM-7
    - DISA-STIG-RHEL-06-000222
  
Remediation Puppet snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
include remove_tftp-server

class remove_tftp-server {
  package { 'tftp-server':
    ensure => 'purged',
  }
}
Remediation Anaconda snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable

package --remove=tftp-server

Rule   Ensure tftp Daemon Uses Secure Mode   [ref]

If running the tftp service is necessary, it should be configured to change its root directory at startup. To do so, ensure /etc/xinetd.d/tftp includes -s as a command line argument, as shown in the following example (which is also the default):

server_args = -s /var/lib/tftpboot

Rationale:

Using the -s option causes the TFTP service to only serve files from the given directory. Serving files from an intentionally-specified directory reduces the risk of sharing files which should remain private.

Severity: 
high
Identifiers and References

Identifiers:  CCE-27272-4

References:  RHEL-06-000338, SV-50502r2_rule, SRG-OS-999999, 11, 12, 13, 14, 15, 16, 18, 3, 5, 8, 9, APO01.06, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, CCI-000366, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, AC-6, AC-17(8), CM-7, PR.AC-3, PR.AC-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000480-GPOS-00227

Group   Xinetd   Group contains 2 rules

[ref]   The xinetd service acts as a dedicated listener for some network services (mostly, obsolete ones) and can be used to provide access controls and perform some logging. It has been largely obsoleted by other features, and it is not installed by default. The older Inetd service is not even available as part of Red Hat Enterprise Linux 6.

Rule   Disable xinetd Service   [ref]

The xinetd service can be disabled with the following command:

$ sudo chkconfig xinetd off

Rationale:

The xinetd service provides a dedicated listener service for some programs, which is no longer necessary for commonly-used network services. Disabling it ensures that these uncommon services are not running, and also prevents attacks against xinetd itself.

Severity: 
medium
Identifiers and References

Identifiers:  CCE-27046-2

References:  RHEL-06-000203, SV-50383r2_rule, SRG-OS-000096, 2.1.7, 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, 3.4.7, CCI-000305, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, AC-17(8), CM-7, PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'xinetd' disable
/sbin/chkconfig --level 0123456 'xinetd' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service xinetd
  service:
    name: xinetd
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_xinetd_disabled
    - medium_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-27046-2
    - NIST-800-53-AC-17(8)
    - NIST-800-53-CM-7
    - NIST-800-171-3.4.7
    - DISA-STIG-RHEL-06-000203
  

Rule   Uninstall xinetd Package   [ref]

The xinetd package can be removed with the following command:

$ sudo yum erase xinetd

Rationale:

Removing the xinetd package decreases the risk of the xinetd service's accidental (or intentional) activation.

Severity: 
medium
Identifiers and References

Identifiers:  CCE-27005-8

References:  RHEL-06-000204, SV-50385r1_rule, SRG-OS-000096, 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-000305, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, AC-17(8), CM-7, PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:disable
# Function to remove packages on RHEL, Fedora, Debian, and possibly other systems.
#
# Example Call(s):
#
#     package_remove telnet-server
#
function package_remove {

# Load function arguments into local variables
local package="$1"

# Check sanity of the input
if [ $# -ne "1" ]
then
  echo "Usage: package_remove 'package_name'"
  echo "Aborting."
  exit 1
fi

if which dnf ; then
  if rpm -q --quiet "$package"; then
    dnf remove -y "$package"
  fi
elif which yum ; then
  if rpm -q --quiet "$package"; then
    yum remove -y "$package"
  fi
elif which apt-get ; then
  apt-get remove -y "$package"
else
  echo "Failed to detect available packaging system, tried dnf, yum and apt-get!"
  echo "Aborting."
  exit 1
fi

}

package_remove xinetd
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Ensure xinetd is removed
  package:
    name: xinetd
    state: absent
  tags:
    - package_xinetd_removed
    - medium_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-27005-8
    - NIST-800-53-AC-17(8)
    - NIST-800-53-CM-7
    - DISA-STIG-RHEL-06-000204
  
Remediation Puppet snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
include remove_xinetd

class remove_xinetd {
  package { 'xinetd':
    ensure => 'purged',
  }
}
Remediation Anaconda snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable

package --remove=xinetd
Group   FTP Server   Group contains 2 groups and 4 rules

[ref]   FTP is a common method for allowing remote access to files. Like telnet, the FTP protocol is unencrypted, which means that passwords and other data transmitted during the session can be captured and that the session is vulnerable to hijacking. Therefore, running the FTP server software is not recommended.

However, there are some FTP server configurations which may be appropriate for some environments, particularly those which allow only read-only anonymous access as a means of downloading data available to the public.

Group   Configure vsftpd to Provide FTP Service if Necessary   Group contains 2 rules

[ref]   The primary vsftpd configuration file is /etc/vsftpd.conf, if that file exists, or /etc/vsftpd/vsftpd.conf if it does not.

Rule   Create Warning Banners for All FTP Users   [ref]

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.

Severity: 
medium
Identifiers and References

Identifiers:  CCE-27145-2

References:  SRG-OS-000023, RHEL-06-000348, SV-50400r3_rule, CCI-000048

Rule   Enable Logging of All FTP Transactions   [ref]

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

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.
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.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27142-9

References:  SRG-OS-000037, RHEL-06-000339, SV-50503r2_rule

Group   Disable vsftpd if Possible   Group contains 2 rules

[ref]   To minimize attack surface, disable vsftpd if at all possible.

Rule   Disable vsftpd Service   [ref]

The vsftpd service can be disabled with the following command:

$ sudo chkconfig vsftpd off

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.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-26948-0

References:  2.2.9, 11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, CCI-001436, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7, PR.IP-1, PR.PT-3

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'vsftpd' disable
/sbin/chkconfig --level 0123456 'vsftpd' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service vsftpd
  service:
    name: vsftpd
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_vsftpd_disabled
    - unknown_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-26948-0
    - NIST-800-53-CM-7
  

Rule   Uninstall vsftpd Package   [ref]

The vsftpd package can be removed with the following command:

 $ sudo yum erase vsftpd

Rationale:

Removing the vsftpd package decreases the risk of its accidental activation.

Severity: 
high
Identifiers and References

Identifiers:  CCE-26687-4

References:  CCI-001436, 11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, CCI-000366, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-6(b), CM-7, PR.IP-1, PR.PT-3, SRG-OS-000480-GPOS-00227

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:disable
# Function to remove packages on RHEL, Fedora, Debian, and possibly other systems.
#
# Example Call(s):
#
#     package_remove telnet-server
#
function package_remove {

# Load function arguments into local variables
local package="$1"

# Check sanity of the input
if [ $# -ne "1" ]
then
  echo "Usage: package_remove 'package_name'"
  echo "Aborting."
  exit 1
fi

if which dnf ; then
  if rpm -q --quiet "$package"; then
    dnf remove -y "$package"
  fi
elif which yum ; then
  if rpm -q --quiet "$package"; then
    yum remove -y "$package"
  fi
elif which apt-get ; then
  apt-get remove -y "$package"
else
  echo "Failed to detect available packaging system, tried dnf, yum and apt-get!"
  echo "Aborting."
  exit 1
fi

}

package_remove vsftpd
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Ensure vsftpd is removed
  package:
    name: vsftpd
    state: absent
  tags:
    - package_vsftpd_removed
    - high_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-26687-4
    - NIST-800-53-CM-6(b)
    - NIST-800-53-CM-7
  
Remediation Puppet snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
include remove_vsftpd

class remove_vsftpd {
  package { 'vsftpd':
    ensure => 'purged',
  }
}
Remediation Anaconda snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable

package --remove=vsftpd
Group   SNMP Server   Group contains 1 group and 2 rules

[ref]   The Simple Network Management Protocol allows administrators to monitor the state of network devices, including computers. Older versions of SNMP were well-known for weak security, such as plaintext transmission of the community string (used for authentication) and usage of easily-guessable choices for the community string.

Group   Disable SNMP Server if Possible   Group contains 2 rules

[ref]   The system includes an SNMP daemon that allows for its remote monitoring, though it not installed by default. If it was installed and activated but is not needed, the software should be disabled and removed.

Rule   Uninstall net-snmp Package   [ref]

The net-snmp package provides the snmpd service. The net-snmp package can be removed with the following command:

$ sudo yum erase net-snmp

Rationale:

If there is no need to run SNMP server software, removing the package provides a safeguard against its activation.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-26332-7

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:disable
# Function to remove packages on RHEL, Fedora, Debian, and possibly other systems.
#
# Example Call(s):
#
#     package_remove telnet-server
#
function package_remove {

# Load function arguments into local variables
local package="$1"

# Check sanity of the input
if [ $# -ne "1" ]
then
  echo "Usage: package_remove 'package_name'"
  echo "Aborting."
  exit 1
fi

if which dnf ; then
  if rpm -q --quiet "$package"; then
    dnf remove -y "$package"
  fi
elif which yum ; then
  if rpm -q --quiet "$package"; then
    yum remove -y "$package"
  fi
elif which apt-get ; then
  apt-get remove -y "$package"
else
  echo "Failed to detect available packaging system, tried dnf, yum and apt-get!"
  echo "Aborting."
  exit 1
fi

}

package_remove net-snmp
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Ensure net-snmp is removed
  package:
    name: net-snmp
    state: absent
  tags:
    - package_net-snmp_removed
    - unknown_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-26332-7
  
Remediation Puppet snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
include remove_net-snmp

class remove_net-snmp {
  package { 'net-snmp':
    ensure => 'purged',
  }
}
Remediation Anaconda snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable

package --remove=net-snmp

Rule   Disable snmpd Service   [ref]

The snmpd service can be disabled with the following command:

$ sudo chkconfig snmpd off

Rationale:

Running SNMP software provides a network-based avenue of attack, and should be disabled if not needed.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-26906-8

References:  2.2.14, SRG-OS-000480-VMM-002000

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'snmpd' disable
/sbin/chkconfig --level 0123456 'snmpd' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service snmpd
  service:
    name: snmpd
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_snmpd_disabled
    - unknown_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-26906-8
  
Group   Cron and At Daemons   Group contains 2 rules

[ref]   The cron and at services are used to allow commands to be executed at a later time. The cron service is required by almost all systems to perform necessary maintenance tasks, while at may or may not be required on a given system. Both daemons should be configured defensively.

Rule   Enable cron Service   [ref]

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 chkconfig --level 2345 crond on

Rationale:

Due to its usage for maintenance and security-supporting tasks, enabling the cron daemon is essential.

Severity: 
medium
Identifiers and References

Identifiers:  CCE-27070-2

References:  RHEL-06-000224, SV-50406r2_rule, SRG-OS-999999, 5.1.1, 11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7, PR.IP-1, PR.PT-3

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'crond' disable
/sbin/chkconfig --level 0123456 'crond' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:enable
- name: Enable service crond
  service:
    name: crond
    enabled: "yes"
    state: "started"
  tags:
    - service_crond_enabled
    - medium_severity
    - enable_strategy
    - low_complexity
    - low_disruption
    - CCE-27070-2
    - NIST-800-53-CM-7
    - DISA-STIG-RHEL-06-000224
  when:  # Bare-metal/VM task, not applicable for containers
    - (ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker")

Rule   Disable At Service (atd)   [ref]

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 chkconfig atd off

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.

Severity: 
medium
Identifiers and References

Identifiers:  CCE-27249-2

References:  RHEL-06-000262, SV-50442r3_rule, SRG-OS-000096, 11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, CCI-000381, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7, PR.IP-1, PR.PT-3

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'atd' disable
/sbin/chkconfig --level 0123456 'atd' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service atd
  service:
    name: atd
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_atd_disabled
    - medium_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-27249-2
    - NIST-800-53-CM-7
    - DISA-STIG-RHEL-06-000262
  when:  # Bare-metal/VM task, not applicable for containers
    - (ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker")
Group   X Window System   Group contains 1 group and 2 rules

[ref]   The X Window System implementation included with the system is called X.org.

Group   Disable X Windows   Group contains 2 rules

[ref]   Unless there is a mission-critical reason for the system to run a graphical user interface, ensure X is not set to start automatically at boot and remove the X Windows software packages. There is usually no reason to run X Windows on a dedicated server system, as it increases the system's attack surface and consumes system resources. Administrators of server systems should instead login via SSH or on the text console.

Rule   Remove the X Windows Package Group   [ref]

By removing the xorg-x11-server-common package, the system no longer has X Windows installed. If X Windows is not installed then the system cannot boot into graphical user mode. This prevents the system from being accidentally or maliciously booted into a graphical.target mode. To do so, run the following command:

$ sudo yum groupremove "X Window System"
$ sudo yum remove xorg-x11-server-common

Rationale:

Unnecessary service packages must not be installed to decrease the attack surface of the system. X windows has a long history of security vulnerabilities and should not be installed unless approved and documented.

Severity: 
medium
Identifiers and References

Identifiers:  CCE-27198-1

References:  RHEL-06-000291, SV-50477r2_rule, SRG-OS-999999, 2.2.2, 12, 15, 8, APO13.01, DSS01.04, DSS05.02, DSS05.03, CCI-000366, 4.3.3.6.6, SR 1.13, SR 2.6, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.13.1.1, A.13.2.1, A.14.1.3, A.6.2.1, A.6.2.2, AC-17(8).1(ii), PR.AC-3, PR.PT-4, SRG-OS-000480-GPOS-00227

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:disable
# Function to remove packages on RHEL, Fedora, Debian, and possibly other systems.
#
# Example Call(s):
#
#     package_remove telnet-server
#
function package_remove {

# Load function arguments into local variables
local package="$1"

# Check sanity of the input
if [ $# -ne "1" ]
then
  echo "Usage: package_remove 'package_name'"
  echo "Aborting."
  exit 1
fi

if which dnf ; then
  if rpm -q --quiet "$package"; then
    dnf remove -y "$package"
  fi
elif which yum ; then
  if rpm -q --quiet "$package"; then
    yum remove -y "$package"
  fi
elif which apt-get ; then
  apt-get remove -y "$package"
else
  echo "Failed to detect available packaging system, tried dnf, yum and apt-get!"
  echo "Aborting."
  exit 1
fi

}

package_remove xorg-x11-server-common
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Ensure xorg-x11-server-common is removed
  package:
    name: xorg-x11-server-common
    state: absent
  tags:
    - package_xorg-x11-server-common_removed
    - medium_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-27198-1
    - NIST-800-53-AC-17(8).1(ii)
    - DISA-STIG-RHEL-06-000291
  
Remediation Puppet snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
include remove_xorg-x11-server-common

class remove_xorg-x11-server-common {
  package { 'xorg-x11-server-common':
    ensure => 'purged',
  }
}
Remediation Anaconda snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable

package --remove=xorg-x11-server-common

Rule   Disable X Windows Startup By Setting Runlevel   [ref]

Setting the system's runlevel to 3 will prevent automatic startup of the X server. To do so, ensure the following line in /etc/inittab features a 3 as shown:

id:3:initdefault:

Rationale:

Unnecessary services should be disabled to decrease the attack surface of the system.

Severity: 
medium
Identifiers and References

Identifiers:  CCE-27119-7

References:  RHEL-06-000290, SV-50475r1_rule, SRG-OS-000248, 11, 12, 14, 15, 16, 18, 3, 5, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.03, DSS06.06, CCI-000366, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, AC-3, PR.AC-4, PR.AC-6, PR.PT-3

Group   DNS Server   Group contains 2 groups and 3 rules

[ref]   Most organizations have an operational need to run at least one nameserver. However, there are many common attacks involving DNS server software, and this server software should be disabled on any system on which it is not needed.

Group   Protect DNS Data from Tampering or Attack   Group contains 1 rule

[ref]   This section discusses DNS configuration options which make it more difficult for attackers to gain access to private DNS data or to modify DNS data.

Rule   Disable Dynamic Updates   [ref]

Is there a mission-critical reason to enable the risky dynamic update functionality? If not, edit /etc/named.conf. For each zone specification, correct the following directive if necessary:

zone "example.com " IN {
  allow-update { none; };
  ...
};

Rationale:

Dynamic updates allow remote servers to add, delete, or modify any entries in your zone file. Therefore, they should be considered highly risky, and disabled unless there is a very good reason for their use. If dynamic updates must be allowed, IP-based ACLs are insufficient protection, since they are easily spoofed. Instead, use TSIG keys (see the previous section for an example), and consider using the update-policy directive to restrict changes to only the precise type of change needed.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27105-6

Group   Disable DNS Server   Group contains 2 rules

[ref]   DNS software should be disabled on any systems which does not need to be a nameserver. Note that the BIND DNS server software is not installed on Red Hat Enterprise Linux 6 by default. The remainder of this section discusses secure configuration of systems which must be nameservers.

Rule   Disable named Service   [ref]

The named service can be disabled with the following command:

$ sudo chkconfig named off

Rationale:

All network services involve some risk of compromise due to implementation flaws and should be disabled if possible.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-26873-0

References:  2.2.8, 11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, CCI-000366, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7, PR.IP-1, PR.PT-3

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'named' disable
/sbin/chkconfig --level 0123456 'named' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service named
  service:
    name: named
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_named_disabled
    - unknown_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-26873-0
    - NIST-800-53-CM-7
  

Rule   Uninstall bind Package   [ref]

The named service is provided by the bind package. The bind package can be removed with the following command:

$ sudo yum erase bind

Rationale:

If there is no need to make DNS server software available, removing it provides a safeguard against its activation.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27030-6

References:  11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, CCI-000366, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7, PR.IP-1, PR.PT-3

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:disable
# Function to remove packages on RHEL, Fedora, Debian, and possibly other systems.
#
# Example Call(s):
#
#     package_remove telnet-server
#
function package_remove {

# Load function arguments into local variables
local package="$1"

# Check sanity of the input
if [ $# -ne "1" ]
then
  echo "Usage: package_remove 'package_name'"
  echo "Aborting."
  exit 1
fi

if which dnf ; then
  if rpm -q --quiet "$package"; then
    dnf remove -y "$package"
  fi
elif which yum ; then
  if rpm -q --quiet "$package"; then
    yum remove -y "$package"
  fi
elif which apt-get ; then
  apt-get remove -y "$package"
else
  echo "Failed to detect available packaging system, tried dnf, yum and apt-get!"
  echo "Aborting."
  exit 1
fi

}

package_remove bind
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Ensure bind is removed
  package:
    name: bind
    state: absent
  tags:
    - package_bind_removed
    - unknown_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-27030-6
    - NIST-800-53-CM-7
  
Remediation Puppet snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
include remove_bind

class remove_bind {
  package { 'bind':
    ensure => 'purged',
  }
}
Remediation Anaconda snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable

package --remove=bind
Group   LDAP   Group contains 1 group and 1 rule

[ref]   LDAP is a popular directory service, that is, a standardized way of looking up information from a central database. Red Hat Enterprise Linux 6 includes software that enables a system to act as both an LDAP client and server.

Group   Configure OpenLDAP Clients   Group contains 1 rule

[ref]   This section provides information on which security settings are important to configure in OpenLDAP clients by manually editing the appropriate configuration files. Red Hat Enterprise Linux 6 provides an automated configuration tool called authconfig and a graphical wrapper for authconfig called system-config-authentication. However, these tools do not provide as much control over configuration as manual editing of configuration files. The authconfig tools do not allow you to specify locations of SSL certificate files, which is useful when trying to use SSL cleanly across several protocols. Installation and configuration of OpenLDAP on Red Hat Enterprise Linux 6 is available at https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Deployment_Guide/ch-Directory_Servers.html.

Warning:  Before configuring any system to be an LDAP client, ensure that a working LDAP server is present on the network.

Rule   Configure LDAP Client to Use TLS For All Transactions   [ref]

This check verifies that Red Hat Enterprise Linux 6 implements cryptography to protect the integrity of remote LDAP authentication sessions.

To determine if LDAP is being used for authentication, use the following command:

$ sudo grep -i useldapauth /etc/sysconfig/authconfig


If USELDAPAUTH=yes, then LDAP is being used. To check if LDAP is configured to use TLS, use the following command:
$ sudo grep -i ssl /etc/pam_ldap.conf

Rationale:

Without cryptographic integrity protections, information can be altered by unauthorized users without detection. The ssl directive specifies whether to use TLS or not. If not specified it will default to no. It should be set to start_tls rather than doing LDAP over SSL.

Severity: 
medium
Identifiers and References

Identifiers:  CCE-26690-8

References:  CCI-000776, CCI-000778, RHEL-06-000252, 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-001453, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, AC-17(2), CM-7, PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000250-GPOS-00093

Remediation Shell script:   (show)



# Use LDAP for authentication
# Function to replace configuration setting in config file or add the configuration setting if
# it does not exist.
#
# Expects arguments:
#
# config_file:		Configuration file that will be modified
# key:			Configuration option to change
# value:		Value of the configuration option to change
# cce:			The CCE identifier or '@CCENUM@' if no CCE identifier exists
# format:		The printf-like format string that will be given stripped key and value as arguments,
#			so e.g. '%s=%s' will result in key=value subsitution (i.e. without spaces around =)
#
# Optional arugments:
#
# format:		Optional argument to specify the format of how key/value should be
# 			modified/appended in the configuration file. The default is key = value.
#
# Example Call(s):
#
#     With default format of 'key = value':
#     replace_or_append '/etc/sysctl.conf' '^kernel.randomize_va_space' '2' '@CCENUM@'
#
#     With custom key/value format:
#     replace_or_append '/etc/sysconfig/selinux' '^SELINUX=' 'disabled' '@CCENUM@' '%s=%s'
#
#     With a variable:
#     replace_or_append '/etc/sysconfig/selinux' '^SELINUX=' $var_selinux_state '@CCENUM@' '%s=%s'
#
function replace_or_append {
  local default_format='%s = %s' case_insensitive_mode=yes sed_case_insensitive_option='' grep_case_insensitive_option=''
  local config_file=$1
  local key=$2
  local value=$3
  local cce=$4
  local format=$5

  if [ "$case_insensitive_mode" = yes ]; then
    sed_case_insensitive_option="i"
    grep_case_insensitive_option="-i"
  fi
  [ -n "$format" ] || format="$default_format"
  # Check sanity of the input
  [ $# -ge "3" ] || { echo "Usage: replace_or_append <config_file_location> <key_to_search> <new_value> [<CCE number or literal '@CCENUM@' if unknown>] [printf-like format, default is '$default_format']" >&2; exit 1; }

  # Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
  # Otherwise, regular sed command will do.
  sed_command=('sed' '-i')
  if test -L "$config_file"; then
    sed_command+=('--follow-symlinks')
  fi

  # Test that the cce arg is not empty or does not equal @CCENUM@.
  # If @CCENUM@ exists, it means that there is no CCE assigned.
  if [ -n "$cce" ] && [ "$cce" != '@CCENUM@' ]; then
    cce="CCE-${cce}"
  else
    cce="CCE"
  fi

  # Strip any search characters in the key arg so that the key can be replaced without
  # adding any search characters to the config file.
  stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "$key")

  # shellcheck disable=SC2059
  printf -v formatted_output "$format" "$stripped_key" "$value"

  # If the key exists, change it. Otherwise, add it to the config_file.
  # We search for the key string followed by a word boundary (matched by \>),
  # so if we search for 'setting', 'setting2' won't match.
  if LC_ALL=C grep -q -m 1 $grep_case_insensitive_option -e "${key}\\>" "$config_file"; then
    "${sed_command[@]}" "s/${key}\\>.*/$formatted_output/g$sed_case_insensitive_option" "$config_file"
  else
    # \n is precaution for case where file ends without trailing newline
    printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "$config_file" >> "$config_file"
    printf '%s\n' "$formatted_output" >> "$config_file"
  fi
}

replace_or_append '/etc/sysconfig/authconfig' 'USELDAPAUTH' 'yes' 'CCE-26690-8' '%s=%s'

# Configure client to use TLS for all authentications
# Function to replace configuration setting in config file or add the configuration setting if
# it does not exist.
#
# Expects arguments:
#
# config_file:		Configuration file that will be modified
# key:			Configuration option to change
# value:		Value of the configuration option to change
# cce:			The CCE identifier or '@CCENUM@' if no CCE identifier exists
# format:		The printf-like format string that will be given stripped key and value as arguments,
#			so e.g. '%s=%s' will result in key=value subsitution (i.e. without spaces around =)
#
# Optional arugments:
#
# format:		Optional argument to specify the format of how key/value should be
# 			modified/appended in the configuration file. The default is key = value.
#
# Example Call(s):
#
#     With default format of 'key = value':
#     replace_or_append '/etc/sysctl.conf' '^kernel.randomize_va_space' '2' '@CCENUM@'
#
#     With custom key/value format:
#     replace_or_append '/etc/sysconfig/selinux' '^SELINUX=' 'disabled' '@CCENUM@' '%s=%s'
#
#     With a variable:
#     replace_or_append '/etc/sysconfig/selinux' '^SELINUX=' $var_selinux_state '@CCENUM@' '%s=%s'
#
function replace_or_append {
  local default_format='%s = %s' case_insensitive_mode=yes sed_case_insensitive_option='' grep_case_insensitive_option=''
  local config_file=$1
  local key=$2
  local value=$3
  local cce=$4
  local format=$5

  if [ "$case_insensitive_mode" = yes ]; then
    sed_case_insensitive_option="i"
    grep_case_insensitive_option="-i"
  fi
  [ -n "$format" ] || format="$default_format"
  # Check sanity of the input
  [ $# -ge "3" ] || { echo "Usage: replace_or_append <config_file_location> <key_to_search> <new_value> [<CCE number or literal '@CCENUM@' if unknown>] [printf-like format, default is '$default_format']" >&2; exit 1; }

  # Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
  # Otherwise, regular sed command will do.
  sed_command=('sed' '-i')
  if test -L "$config_file"; then
    sed_command+=('--follow-symlinks')
  fi

  # Test that the cce arg is not empty or does not equal @CCENUM@.
  # If @CCENUM@ exists, it means that there is no CCE assigned.
  if [ -n "$cce" ] && [ "$cce" != '@CCENUM@' ]; then
    cce="CCE-${cce}"
  else
    cce="CCE"
  fi

  # Strip any search characters in the key arg so that the key can be replaced without
  # adding any search characters to the config file.
  stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "$key")

  # shellcheck disable=SC2059
  printf -v formatted_output "$format" "$stripped_key" "$value"

  # If the key exists, change it. Otherwise, add it to the config_file.
  # We search for the key string followed by a word boundary (matched by \>),
  # so if we search for 'setting', 'setting2' won't match.
  if LC_ALL=C grep -q -m 1 $grep_case_insensitive_option -e "${key}\\>" "$config_file"; then
    "${sed_command[@]}" "s/${key}\\>.*/$formatted_output/g$sed_case_insensitive_option" "$config_file"
  else
    # \n is precaution for case where file ends without trailing newline
    printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "$config_file" >> "$config_file"
    printf '%s\n' "$formatted_output" >> "$config_file"
  fi
}

replace_or_append '/etc/nslcd.conf' 'ssl' 'start_tls' 'CCE-26690-8' '%s %s'
Group   Mail Server Software   Group contains 2 rules

[ref]   Mail servers are used to send and receive email over the network. Mail is a very common service, and Mail Transfer Agents (MTAs) are obvious targets of network attack. Ensure that systems are not running MTAs unnecessarily, and configure needed MTAs as defensively as possible.

Very few systems at any site should be configured to directly receive email over the network. Users should instead use mail client programs to retrieve email from a central server that supports protocols such as IMAP or POP3. However, it is normal for most systems to be independently capable of sending email, for instance so that cron jobs can report output to an administrator. Most MTAs, including Postfix, support a submission-only mode in which mail can be sent from the local system to a central site MTA (or directly delivered to a local account), but the system still cannot receive mail directly over a network.

The alternatives program in Red Hat Enterprise Linux 6 permits selection of other mail server software (such as Sendmail), but Postfix is the default and is preferred. Postfix was coded with security in mind and can also be more effectively contained by SELinux as its modular design has resulted in separate processes performing specific actions. More information is available on its website, http://www.postfix.org.

Rule   Uninstall Sendmail Package   [ref]

Sendmail is not the default mail transfer agent and is not installed by default. The sendmail package can be removed with the following command:

$ sudo yum erase sendmail

Rationale:

The sendmail software was not developed with security in mind and its design prevents it from being effectively contained by SELinux. Postfix should be used instead.

Severity: 
medium
Identifiers and References

Identifiers:  CCE-27515-6

References:  RHEL-06-000288, SV-50472r1_rule, SRG-OS-999999, 11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7, PR.IP-1, PR.PT-3

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:disable
# Function to remove packages on RHEL, Fedora, Debian, and possibly other systems.
#
# Example Call(s):
#
#     package_remove telnet-server
#
function package_remove {

# Load function arguments into local variables
local package="$1"

# Check sanity of the input
if [ $# -ne "1" ]
then
  echo "Usage: package_remove 'package_name'"
  echo "Aborting."
  exit 1
fi

if which dnf ; then
  if rpm -q --quiet "$package"; then
    dnf remove -y "$package"
  fi
elif which yum ; then
  if rpm -q --quiet "$package"; then
    yum remove -y "$package"
  fi
elif which apt-get ; then
  apt-get remove -y "$package"
else
  echo "Failed to detect available packaging system, tried dnf, yum and apt-get!"
  echo "Aborting."
  exit 1
fi

}

package_remove sendmail
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Ensure sendmail is removed
  package:
    name: sendmail
    state: absent
  tags:
    - package_sendmail_removed
    - medium_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-27515-6
    - NIST-800-53-CM-7
    - DISA-STIG-RHEL-06-000288
  when:  # Bare-metal/VM task, not applicable for containers
    - (ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker")
Remediation Puppet snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
include remove_sendmail

class remove_sendmail {
  package { 'sendmail':
    ensure => 'purged',
  }
}
Remediation Anaconda snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable

package --remove=sendmail

Rule   Enable Postfix Service   [ref]

The Postfix mail transfer agent is used for local mail delivery within the system. The default configuration only listens for connections to the default SMTP port (port 25) on the loopback interface (127.0.0.1). It is recommended to leave this service enabled for local mail delivery. The postfix service can be enabled with the following command:

$ sudo chkconfig --level 2345 postfix on

Rationale:

Local mail delivery is essential to some system maintenance and notification tasks.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-26325-1

References:  SRG-OS-999999, RHEL-06-000287, SV-50470r1_rule

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'postfix' disable
/sbin/chkconfig --level 0123456 'postfix' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:enable
- name: Enable service postfix
  service:
    name: postfix
    enabled: "yes"
    state: "started"
  tags:
    - service_postfix_enabled
    - unknown_severity
    - enable_strategy
    - low_complexity
    - low_disruption
    - CCE-26325-1
    - DISA-STIG-RHEL-06-000287
  when:  # Bare-metal/VM task, not applicable for containers
    - (ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker")
Group   Samba(SMB) Microsoft Windows File Sharing Server   Group contains 2 groups and 4 rules

[ref]   When properly configured, the Samba service allows Linux systems to provide file and print sharing to Microsoft Windows systems. There are two software packages that provide Samba support. The first, samba-client, provides a series of command line tools that enable a client system to access Samba shares. The second, simply labeled samba, provides the Samba service. It is this second package that allows a Linux system to act as an Active Directory server, a domain controller, or as a domain member. Only the samba-client package is installed by default.

Group   Disable Samba if Possible   Group contains 1 rule

[ref]   Even after the Samba server package has been installed, it will remain disabled. Do not enable this service unless it is absolutely necessary to provide Microsoft Windows file and print sharing functionality.

Rule   Disable Samba   [ref]

The smb service can be disabled with the following command:

$ sudo chkconfig smb off

Rationale:

Running a Samba server provides a network-based avenue of attack, and should be disabled if not needed.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27143-7

References:  2.2.12, CCI-001436

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'smb' disable
/sbin/chkconfig --level 0123456 'smb' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service smb
  service:
    name: smb
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_smb_disabled
    - unknown_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-27143-7
  
Group   Configure Samba if Necessary   Group contains 3 rules

[ref]   All settings for the Samba daemon can be found in /etc/samba/smb.conf. Settings are divided between a [global] configuration section and a series of user created share definition sections meant to describe file or print shares on the system. By default, Samba will operate in user mode and allow client systems to access local home directories and printers. It is recommended that these settings be changed or that additional limitations be set in place.

Rule   Disable Root Access to SMB Shares   [ref]

Administrators should not use administrator accounts to access Samba file and printer shares. Disable the root user and the wheel administrator group:

[share]
  invalid users = root @wheel
If administrator accounts cannot be disabled, ensure that local system passwords and Samba service passwords do not match.

Rationale:

Typically, administrator access is required when Samba must create user and system accounts and shares. Domain member servers and standalone servers may not need administrator access at all. If that is the case, add the invalid users parameter to [global] instead.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27533-9

Rule   Require Client SMB Packet Signing, if using smbclient   [ref]

To require samba clients running smbclient to use packet signing, add the following to the [global] section of the Samba configuration file, /etc/samba/smb.conf:

client signing = mandatory
Requiring samba clients such as smbclient to use packet signing ensures they can only communicate with servers that support packet signing.

Rationale:

Packet signing can prevent man-in-the-middle attacks which modify SMB packets in transit.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-26328-5

References:  SRG-OS-999999, RHEL-06-000272, SV-50457r1_rule

Remediation Shell script:   (show)

######################################################################
#By Luke "Brisk-OH" Brisk
#luke.brisk@boeing.com or luke.brisk@gmail.com
######################################################################

CLIENTSIGNING=$( grep -ic 'client signing' /etc/samba/smb.conf )

if [ "$CLIENTSIGNING" -eq 0 ];  then
	# Add to global section
	sed -i 's/\[global\]/\[global\]\n\n\tclient signing = mandatory/g' /etc/samba/smb.conf
else
	sed -i 's/[[:blank:]]*client[[:blank:]]signing[[:blank:]]*=[[:blank:]]*no/        client signing = mandatory/g' /etc/samba/smb.conf
fi
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:medium
Strategy:configure
- name: Check if /etc/samba/smb.conf exists
  stat:
    path: /etc/samba/smb.conf
  register: st_smb
  tags:
    - require_smb_client_signing
    - unknown_severity
    - configure_strategy
    - low_complexity
    - medium_disruption
    - CCE-26328-5
    - DISA-STIG-RHEL-06-000272
  

- name: Require Client SMB Packet Signing, if using smbclient
  lineinfile:
    dest: /etc/samba/smb.conf
    line: client signing = mandatory
    state: present
    insertafter: [global]
  when: st_smb.stat.exists and True
  tags:
    - require_smb_client_signing
    - unknown_severity
    - configure_strategy
    - low_complexity
    - medium_disruption
    - CCE-26328-5
    - DISA-STIG-RHEL-06-000272

Rule   Require Client SMB Packet Signing, if using mount.cifs   [ref]

Require packet signing of clients who mount Samba shares using the mount.cifs program (e.g., those who specify shares in /etc/fstab). To do so, ensure signing options (either sec=krb5i or sec=ntlmv2i) are used.

See the mount.cifs(8) man page for more information. A Samba client should only communicate with servers who can support SMB packet signing.

Rationale:

Packet signing can prevent man-in-the-middle attacks which modify SMB packets in transit.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-26792-2

References:  SRG-OS-999999, RHEL-06-000273, SV-50458r2_rule

Group   Web Server   Group contains 11 groups and 22 rules

[ref]   The web server is responsible for providing access to content via the HTTP protocol. Web servers represent a significant security risk because:

  • The HTTP port is commonly probed by malicious sources
  • Web server software is very complex, and includes a long history of vulnerabilities
  • The HTTP protocol is unencrypted and vulnerable to passive monitoring


The system's default web server software is Apache 2 and is provided in the RPM package httpd.

Group   Disable Apache if Possible   Group contains 1 rule

[ref]   If Apache was installed and activated, but the system does not need to act as a web server, then it should be disabled and removed from the system.

Rule   Uninstall httpd Package   [ref]

The httpd package can be removed with the following command:

 $ sudo yum erase httpd

Rationale:

If there is no need to make the web server software available, removing it provides a safeguard against its activation.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27133-8

References:  11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7, PR.IP-1, PR.PT-3

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:disable
# Function to remove packages on RHEL, Fedora, Debian, and possibly other systems.
#
# Example Call(s):
#
#     package_remove telnet-server
#
function package_remove {

# Load function arguments into local variables
local package="$1"

# Check sanity of the input
if [ $# -ne "1" ]
then
  echo "Usage: package_remove 'package_name'"
  echo "Aborting."
  exit 1
fi

if which dnf ; then
  if rpm -q --quiet "$package"; then
    dnf remove -y "$package"
  fi
elif which yum ; then
  if rpm -q --quiet "$package"; then
    yum remove -y "$package"
  fi
elif which apt-get ; then
  apt-get remove -y "$package"
else
  echo "Failed to detect available packaging system, tried dnf, yum and apt-get!"
  echo "Aborting."
  exit 1
fi

}

package_remove httpd
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Ensure httpd is removed
  package:
    name: httpd
    state: absent
  tags:
    - package_httpd_removed
    - unknown_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-27133-8
    - NIST-800-53-CM-7
  
Remediation Puppet snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
include remove_httpd

class remove_httpd {
  package { 'httpd':
    ensure => 'purged',
  }
}
Remediation Anaconda snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable

package --remove=httpd
Group   Secure Apache Configuration   Group contains 9 groups and 21 rules

[ref]   The httpd configuration file is /etc/httpd/conf/httpd.conf. Apply the recommendations in the remainder of this section to this file.

Group   Restrict Web Server Information Leakage   Group contains 1 rule

[ref]   The ServerTokens and ServerSignature directives determine how much information the web server discloses about the configuration of the system.

Rule   Set httpd ServerTokens Directive to Prod   [ref]

ServerTokens Prod restricts information in page headers, returning only the word "Apache."

Add or correct the following directive in /etc/httpd/conf/httpd.conf:

ServerTokens Prod

Rationale:

Information disclosed to clients about the configuration of the web server and system could be used to plan an attack on the given system. This information disclosure should be restricted to a minimum.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27425-8

References:  11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7, PR.IP-1, PR.PT-3

Group   Configure Operating System to Protect Web Server   Group contains 1 group and 2 rules

[ref]   The following configuration steps should be taken on the system which hosts the web server, in order to provide as safe an environment as possible for the web server.

Group   Restrict File and Directory Access   Group contains 2 rules

[ref]   Minimize access to critical httpd files and directories.

Rule   Set Permissions on the /etc/httpd/conf/ Directory   [ref]

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

$ sudo chmod 0750 /etc/http/conf

Rationale:

Access to the web server's configuration files may allow an unauthorized user or attacker to access information about the web server or alter the server's configuration files.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27487-8

Rule   Set Permissions on All Configuration Files Inside /etc/httpd/conf/   [ref]

To properly set the permissions of /etc/http/conf/*, run the command:

$ sudo chmod 0640 /etc/http/conf/*

Rationale:

Access to the web server's configuration files may allow an unauthorized user or attacker to access information about the web server or to alter the server's configuration files.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27316-9

References:  11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7, PR.IP-1, PR.PT-3

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:configure
find /etc/httpd/conf -regex '^/etc/httpd/conf/.*$' -exec chmod 0640 {} \;
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:configure
- name: Find /etc/httpd/conf file(s)
  find:
    paths: "/etc/httpd/conf"
    patterns: "^.*$"
  register: files_found
  tags:
    - file_permissions_httpd_server_conf_files
    - unknown_severity
    - configure_strategy
    - low_complexity
    - low_disruption
    - CCE-27316-9
    - NIST-800-53-CM-7

- name: Set permissions for /etc/httpd/conf file(s)
  file:
    path: "{{ item.path }}"
    mode: 0640
  with_items:
    - "{{ files_found.files }}"
  tags:
    - file_permissions_httpd_server_conf_files
    - unknown_severity
    - configure_strategy
    - low_complexity
    - low_disruption
    - CCE-27316-9
    - NIST-800-53-CM-7
  
Group   Use Appropriate Modules to Improve httpd's Security   Group contains 2 groups and 2 rules

[ref]   Among the modules available for httpd are several whose use may improve the security of the web server installation. This section recommends and discusses the deployment of security-relevant modules.

Group   Deploy mod_security   Group contains 1 rule

[ref]   The security module provides an application level firewall for httpd. Following its installation with the base ruleset, specific configuration advice can be found at http://www.modsecurity.org/ to design a policy that best matches the security needs of the web applications. Usage of mod_security is highly recommended for some environments, but it should be noted this module does not ship with Red Hat Enterprise Linux itself, and instead is provided via Extra Packages for Enterprise Linux (EPEL). For more information on EPEL please refer to http://fedoraproject.org/wiki/EPEL.

Rule   Install mod_security   [ref]

Install the security module: The mod_security package can be installed with the following command:

$ sudo yum install mod_security

Rationale:

mod_security provides an additional level of protection for the web server by enabling the administrator to implement content access policies and filters at the application layer.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27525-5

Group   Deploy mod_ssl   Group contains 1 rule

[ref]   Because HTTP is a plain text protocol, all traffic is susceptible to passive monitoring. If there is a need for confidentiality, SSL should be configured and enabled to encrypt content.

Note: mod_nss is a FIPS 140-2 certified alternative to mod_ssl. The modules share a considerable amount of code and should be nearly identical in functionality. If FIPS 140-2 validation is required, then mod_nss should be used. If it provides some feature or its greater compatibility is required, then mod_ssl should be used.

Rule   Install mod_ssl   [ref]

Install the mod_ssl module: The mod_ssl package can be installed with the following command:

$ sudo yum install mod_ssl

Rationale:

mod_ssl provides encryption capabilities for the httpd Web server. Unencrypted content is transmitted in plain text which could be passively monitored and accessed by unauthorized parties.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27403-5

Group   Directory Restrictions   Group contains 4 rules

[ref]   The Directory tags in the web server configuration file allow finer grained access control for a specified directory. All web directories should be configured on a case-by-case basis, allowing access only where needed.

Rule   Restrict Web Directory   [ref]

The default configuration for the web (/var/www/html) Directory allows directory indexing (Indexes) and the following of symbolic links (FollowSymLinks). Neither of these is recommended.

The /var/www/html directory hierarchy should not be viewable via the web, and symlinks should only be followed if the owner of the symlink also owns the linked file.

Ensure that this policy is adhered to by altering the related section of the configuration:

<Directory "/var/www/html">
#  ...
   Options SymLinksIfOwnerMatch
#  ...
</Directory>

Rationale:

Access to the web server's directory hierarchy could allow access to unauthorized files by web clients. Following symbolic links could also allow such access.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27574-3

Rule   Restrict Other Critical Directories   [ref]

All accessible web directories should be configured with similarly restrictive settings. The Options directive should be limited to necessary functionality and the AllowOverride directive should be used only if needed. The Order and Deny access control tags should be used to deny access by default, allowing access only where necessary.

Rationale:

Directories accessible from a web client should be configured with the least amount of access possible in order to avoid unauthorized access to restricted content or server information.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27565-1

Rule   Restrict Root Directory   [ref]

The httpd root directory should always have the most restrictive configuration enabled.

<Directory / >
   Options None
   AllowOverride None
   Order allow,deny
</Directory>

Rationale:

The Web Server's root directory content should be protected from unauthorized access by web clients.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27009-0

Rule   Limit Available Methods   [ref]

Web server methods are defined in section 9 of RFC 2616 ( http://www.ietf.org/rfc/rfc2616.txt). If a web server does not require the implementation of all available methods, they should be disabled.

Note: GET and POST are the most common methods. A majority of the others are limited to the WebDAV protocol.

<Directory /var/www/html>
# ...
   # Only allow specific methods (this command is case-sensitive!)
   <LimitExcept GET POST>
      Order allow,deny
   </LimitExcept>
# ...
</Directory>

Rationale:

Minimizing the number of available methods to the web client reduces risk by limiting the capabilities allowed by the web server.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27581-8

Group   Minimize Web Server Loadable Modules   Group contains 1 group and 12 rules

[ref]   A default installation of httpd includes a plethora of dynamically shared objects (DSO) that are loaded at run-time. Unlike the aforementioned compiled-in modules, a DSO can be disabled in the configuration file by removing the corresponding LoadModule directive.

Note: A DSO only provides additional functionality if associated directives are included in the httpd configuration file. It should also be noted that removing a DSO will produce errors on httpd startup if the configuration file contains directives that apply to that module. Refer to http://httpd.apache.org/docs/ for details on which directives are associated with each DSO.

Following each DSO removal, the configuration can be tested with the following command to check if everything still works:

$ sudo service httpd configtest
The purpose of each of the modules loaded by default will now be addressed one at a time. If none of a module's directives are being used, remove it.

Group   httpd Core Modules   Group contains 12 rules

[ref]   These modules comprise a basic subset of modules that are likely needed for base httpd functionality; ensure they are not commented out in /etc/httpd/conf/httpd.conf:

LoadModule auth_basic_module modules/mod_auth_basic.so
LoadModule authn_default_module modules/mod_authn_default.so
LoadModule authz_host_module modules/mod_authz_host.so
LoadModule authz_user_module modules/mod_authz_user.so
LoadModule authz_groupfile_module modules/mod_authz_groupfile.so
LoadModule authz_default_module modules/mod_authz_default.so
LoadModule log_config_module modules/mod_log_config.so
LoadModule logio_module modules/mod_logio.so
LoadModule setenvif_module modules/mod_setenvif.so
LoadModule mime_module modules/mod_mome.so
LoadModule autoindex_module modules/mod_autoindex.so
LoadModule negotiation_module modules/mod_negotiation.so
LoadModule dir_module modules/mod_dir.so
LoadModule alias_module modules/mod_alias.so
Minimizing the number of loadable modules available to the web server reduces risk by limiting the capabilities allowed by the web server.

Rule   Disable LDAP Support   [ref]

The ldap module provides HTTP authentication via an LDAP directory. If its functionality is unnecessary, comment out the related modules:

#LoadModule ldap_module modules/mod_ldap.so
#LoadModule authnz_ldap_module modules/mod_authnz_ldap.so
If LDAP is to be used, SSL encryption should be used as well.

Rationale:

Minimizing the number of loadable modules available to the web server reduces risk by limiting the capabilities allowed by the web server.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27395-3

Rule   Disable CGI Support   [ref]

The cgi module allows HTML to interact with the CGI web programming language.

If this functionality is unnecessary, comment out the module:

#LoadModule cgi_module modules/mod_cgi.so
If the web server requires the use of CGI, enable mod_cgi.

Rationale:

Minimizing the number of loadable modules available to the web server reduces risk by limiting the capabilities allowed by the web server.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27362-3

Rule   Disable URL Correction on Misspelled Entries   [ref]

The speling module attempts to find a document match by allowing one misspelling in an otherwise failed request. If this functionality is unnecessary, comment out the module:

#LoadModule speling_module modules/mod_speling.so
This functionality weakens server security by making site enumeration easier.

Rationale:

Minimizing the number of loadable modules available to the web server reduces risk by limiting the capabilities allowed by the web server.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27276-5

Rule   Disable Server Activity Status   [ref]

The status module provides real-time access to statistics on the internal operation of the web server. This may constitute an unnecessary information leak and should be disabled unless necessary. To do so, comment out the related module:

#LoadModule status_module modules/mod_status.so
If there is a critical need for this module, ensure that access to the status page is properly restricted to a limited set of hosts in the status handler configuration.

Rationale:

Minimizing the number of loadable modules available to the web server reduces risk by limiting the capabilities allowed by the web server.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27468-8

Rule   Disable HTTP Digest Authentication   [ref]

The auth_digest module provides encrypted authentication sessions. If this functionality is unnecessary, comment out the related module:

#LoadModule auth_digest_module modules/mod_auth_digest.so

Rationale:

Minimizing the number of loadable modules available to the web server reduces risk by limiting the capabilities allowed by the web server.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27553-7

Rule   Disable WebDAV (Distributed Authoring and Versioning)   [ref]

WebDAV is an extension of the HTTP protocol that provides distributed and collaborative access to web content. If its functionality is unnecessary, comment out the related modules:

#LoadModule dav_module modules/mod_dav.so
#LoadModule dav_fs_module modules/mod_dav_fs.so
If there is a critical need for WebDAV, extra care should be taken in its configuration. Since DAV access allows remote clients to manipulate server files, any location on the server that is DAV enabled should be protected by access controls.

Rationale:

Minimizing the number of loadable modules available to the web server, reduces risk by limiting the capabilities allowed by the web server.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27329-2

Rule   Disable MIME Magic   [ref]

The mime_magic module provides a second layer of MIME support that in most configurations is likely extraneous. If its functionality is unnecessary, comment out the related module:

#LoadModule mime_magic_module modules/mod_mime_magic.so

Rationale:

Minimizing the number of loadable modules available to the web server reduces risk by limiting the capabilities allowed by the web server.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27541-2

Rule   Disable Web Server Configuration Display   [ref]

The info module creates a web page illustrating the configuration of the web server. This can create an unnecessary security leak and should be disabled. If its functionality is unnecessary, comment out the module:

#LoadModule info_module modules/mod_info.so
If there is a critical need for this module, use the Location directive to provide an access control list to restrict access to the information.

Rationale:

Minimizing the number of loadable modules available to the web server reduces risk by limiting the capabilities allowed by the web server.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27507-3

Rule   Disable Cache Support   [ref]

The cache module allows httpd to cache data, optimizing access to frequently accessed content. However, it introduces potential security flaws such as the possibility of circumventing Allow and Deny directives.

If this functionality is unnecessary, comment out the module:

#LoadModule cache_module modules/mod_cache.so
If caching is required, it should not be enabled for any limited-access content.

Rationale:

Minimizing the number of loadable modules available to the web server reduces risk by limiting the capabilities allowed by the web server.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-26859-9

Rule   Disable HTTP mod_rewrite   [ref]

The mod_rewrite module is very powerful and can protect against certain classes of web attacks. However, it is also very complex and has a significant history of vulnerabilities itself. If its functionality is unnecessary, comment out the related module:

#LoadModule rewrite_module modules/mod_rewrite.so

Rationale:

Minimizing the number of loadable modules available to the web server reduces risk by limiting the capabilities allowed by the web server.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27570-1

Rule   Disable Server Side Includes   [ref]

Server Side Includes provide a method of dynamically generating web pages through the insertion of server-side code. However, the technology is also deprecated and introduces significant security concerns. If this functionality is unnecessary, comment out the related module:

#LoadModule include_module modules/mod_include.so
If there is a critical need for Server Side Includes, they should be enabled with the option IncludesNoExec to prevent arbitrary code execution. Additionally, user supplied data should be encoded to prevent cross-site scripting vulnerabilities.

Rationale:

Minimizing the number of loadable modules available to the web server reduces risk by limiting the capabilities allowed by the web server.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27558-6

Rule   Disable Proxy Support   [ref]

The proxy module provides proxying support, allowing httpd to forward requests and serve as a gateway for other servers. If its functionality is unnecessary, comment out the module:

#LoadModule proxy_module modules/mod_proxy.so
If proxy support is needed, load mod_proxy and the appropriate proxy protocol handler module (one of mod_proxy_http, mod_proxy_ftp, or mod_proxy_connect). Additionally, make certain that a server is secure before enabling proxying, as open proxy servers are a security risk. mod_proxy_balancer enables load balancing, but requires that mod status be enabled.

Rationale:

Minimizing the number of loadable modules available to the web server reduces risk by limiting the capabilities allowed by the web server.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27442-3

Group   Network Time Protocol   Group contains 2 rules

[ref]   The Network Time Protocol is used to manage the system clock over a network. Computer clocks are not very accurate, so time will drift unpredictably on unmanaged systems. Central time protocols can be used both to ensure that time is consistent among a network of systems, and that their time is consistent with the outside world.

If every system on a network reliably reports the same time, then it is much easier to correlate log messages in case of an attack. In addition, a number of cryptographic protocols (such as Kerberos) use timestamps to prevent certain types of attacks. If your network does not have synchronized time, these protocols may be unreliable or even unusable.

Depending on the specifics of the network, global time accuracy may be just as important as local synchronization, or not very important at all. If your network is connected to the Internet, using a public timeserver (or one provided by your enterprise) provides globally accurate timestamps which may be essential in investigating or responding to an attack which originated outside of your network.

A typical network setup involves a small number of internal systems operating as NTP servers, and the remainder obtaining time information from those internal servers.

There is a choice between the daemons ntpd and chronyd, which are available from the repositories in the ntp and chrony packages respectively.

The default chronyd daemon can work well when external time references are only intermittently accesible, can perform well even when the network is congested for longer periods of time, can usually synchronize the clock faster and with better time accuracy, and quickly adapts to sudden changes in the rate of the clock, for example, due to changes in the temperature of the crystal oscillator. Chronyd should be considered for all systems which are frequently suspended or otherwise intermittently disconnected and reconnected to a network. Mobile and virtual systems for example.

The ntpd NTP daemon fully supports NTP protocol version 4 (RFC 5905), including broadcast, multicast, manycast clients and servers, and the orphan mode. It also supports extra authentication schemes based on public-key cryptography (RFC 5906). The NTP daemon (ntpd) should be considered for systems which are normally kept permanently on. Systems which are required to use broadcast or multicast IP, or to perform authentication of packets with the Autokey protocol, should consider using ntpd.

Refer to https://docs.fedoraproject.org/en-US/fedora/rawhide/system-administrators-guide/servers/Configuring_NTP_Using_the_chrony_Suite/ for more detailed comparison of features of chronyd and ntpd daemon features respectively, and for further guidance how to choose between the two NTP daemons.

The upstream manual pages at http://chrony.tuxfamily.org/manual.html for chronyd and http://www.ntp.org for ntpd provide additional information on the capabilities and configuration of each of the NTP daemons.

Rule   Enable the NTP Daemon   [ref]

The ntpd service can be enabled with the following command:

$ sudo chkconfig --level 2345 ntpd on

Rationale:

Enabling the ntpd service ensures that the ntpd 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 NTP 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.

Severity: 
medium
Identifiers and References

Identifiers:  CCE-27093-4

References:  CCI-000160, RHEL-06-000247, SV-50421r1_rule, SRG-OS-000056, 1, 14, 15, 16, 3, 5, 6, APO11.04, BAI03.05, DSS05.04, DSS05.07, MEA02.01, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, AU-8(1), PR.PT-1, Req-10.4

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'ntpd' disable
/sbin/chkconfig --level 0123456 'ntpd' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:enable
- name: Enable service ntpd
  service:
    name: ntpd
    enabled: "yes"
    state: "started"
  tags:
    - service_ntpd_enabled
    - medium_severity
    - enable_strategy
    - low_complexity
    - low_disruption
    - CCE-27093-4
    - NIST-800-53-AU-8(1)
    - PCI-DSS-Req-10.4
    - DISA-STIG-RHEL-06-000247
  when:  # Bare-metal/VM task, not applicable for containers
    - (ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker")

Rule   Specify a Remote NTP Server   [ref]

To specify a remote NTP server for time synchronization, edit the file /etc/ntp.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.

Severity: 
medium
Identifiers and References

Identifiers:  CCE-27098-3

References:  CCI-000160, RHEL-06-000248, SV-50422r1_rule, SRG-OS-000056, 1, 14, 15, 16, 3, 5, 6, APO11.04, BAI03.05, DSS05.04, DSS05.07, MEA02.01, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, AU-8(1), PR.PT-1, Req-10.4.1, Req-10.4.3

Group   Base Services   Group contains 22 rules

[ref]   This section addresses the base services that are installed on a Red Hat Enterprise Linux 6 default installation which are not covered in other sections. Some of these services listen on the network and should be treated with particular discretion. Other services are local system utilities that may or may not be extraneous. In general, system services should be disabled if not required.

Rule   Disable Hardware Abstraction Layer Service (haldaemon)   [ref]

The Hardware Abstraction Layer Daemon (haldaemon) collects and maintains information about the system's hardware configuration. This service is required on a workstation running a desktop environment, and may be necessary on any system which deals with removable media or devices. The haldaemon service can be disabled with the following command:

$ sudo chkconfig haldaemon off

Rationale:

The haldaemon provides essential functionality on systems that use removable media or devices, but can be disabled for systems that do not require these.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27086-8

References:  11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7, PR.IP-1, PR.PT-3

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'haldaemon' disable
/sbin/chkconfig --level 0123456 'haldaemon' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service haldaemon
  service:
    name: haldaemon
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_haldaemon_disabled
    - unknown_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-27086-8
    - NIST-800-53-CM-7
  

Rule   Disable D-Bus IPC Service (messagebus)   [ref]

D-Bus provides an IPC mechanism used by a growing list of programs, such as those used for Gnome, Bluetooth, and Avahi. Due to these dependencies, disabling D-Bus may not be practical for many systems. The messagebus service can be disabled with the following command:

$ sudo chkconfig messagebus off

Rationale:

If no services which require D-Bus are needed, then it can be disabled. As a broker for IPC between processes of different privilege levels, it could be a target for attack. However, disabling D-Bus is likely to be impractical for any system which needs to provide a graphical login session.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-26913-4

References:  11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7, PR.IP-1, PR.PT-3

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'messagebus' disable
/sbin/chkconfig --level 0123456 'messagebus' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service messagebus
  service:
    name: messagebus
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_messagebus_disabled
    - unknown_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-26913-4
    - NIST-800-53-CM-7
  

Rule   Disable Advanced Configuration and Power Interface (acpid)   [ref]

The Advanced Configuration and Power Interface Daemon (acpid) dispatches ACPI events (such as power/reset button depressed) to userspace programs. The acpid service can be disabled with the following command:

$ sudo chkconfig acpid off

Rationale:

ACPI support is highly desirable for systems in some network roles, such as laptops or desktops. For other systems, such as servers, it may permit accidental or trivially achievable denial of service situations and disabling it is appropriate.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27061-1

References:  11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7, PR.IP-1, PR.PT-3

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'acpid' disable
/sbin/chkconfig --level 0123456 'acpid' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service acpid
  service:
    name: acpid
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_acpid_disabled
    - unknown_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-27061-1
    - NIST-800-53-CM-7
  

Rule   Disable KDump Kernel Crash Analyzer (kdump)   [ref]

The kdump service provides a kernel crash dump analyzer. It uses the kexec system call to boot a secondary kernel ("capture" kernel) following a system crash, which can load information from the crashed kernel for analysis. The kdump service can be disabled with the following command:

$ sudo chkconfig kdump off

Rationale:

Kernel core dumps may contain the full contents of system memory at the time of the crash. Kernel core dumps consume a considerable amount of disk space and may result in denial of service by exhausting the available space on the target file system partition. Unless the system is used for kernel development or testing, there is little need to run the kdump service.

Severity: 
medium
Identifiers and References

Identifiers:  CCE-26850-8

References:  11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-000366, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, AC-17(8), CM-7, CM-6(b), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000480-GPOS-00227

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'kdump' disable
/sbin/chkconfig --level 0123456 'kdump' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service kdump
  service:
    name: kdump
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_kdump_disabled
    - medium_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-26850-8
    - NIST-800-53-AC-17(8)
    - NIST-800-53-CM-7
    - NIST-800-53-CM-6(b)
  
Remediation Anaconda snippet:   (show)


kdump --disable

Rule   Disable CPU Speed (cpuspeed)   [ref]

The cpuspeed service can adjust the clock speed of supported CPUs based upon the current processing load thereby conserving power and reducing heat. The cpuspeed service can be disabled with the following command:

$ sudo chkconfig cpuspeed off

Rationale:

The cpuspeed service is only necessary if adjusting the CPU clock speed provides benefit. Traditionally this has included laptops (to enhance battery life), but may also apply to server or desktop environments where conserving power is highly desirable or necessary.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-26973-8

References:  11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7, PR.IP-1, PR.PT-3

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'cpuspeed' disable
/sbin/chkconfig --level 0123456 'cpuspeed' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service cpuspeed
  service:
    name: cpuspeed
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_cpuspeed_disabled
    - unknown_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-26973-8
    - NIST-800-53-CM-7
  

Rule   Disable Network Console (netconsole)   [ref]

The netconsole service is responsible for loading the netconsole kernel module, which logs kernel printk messages over UDP to a syslog server. This allows debugging of problems where disk logging fails and serial consoles are impractical. The netconsole service can be disabled with the following command:

$ sudo chkconfig netconsole off

Rationale:

The netconsole service is not necessary unless there is a need to debug kernel panics, which is not common.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27254-2

References:  RHEL-06-000289, SV-50473r2_rule, SRG-OS-000096, 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-000381, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, AC-17(8), CM-7, PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'netconsole' disable
/sbin/chkconfig --level 0123456 'netconsole' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service netconsole
  service:
    name: netconsole
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_netconsole_disabled
    - unknown_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-27254-2
    - NIST-800-53-AC-17(8)
    - NIST-800-53-CM-7
    - DISA-STIG-RHEL-06-000289
  

Rule   Disable Certmonger Service (certmonger)   [ref]

Certmonger is a D-Bus based service that attempts to simplify interaction with certifying authorities on networks which use public-key infrastructure. It is often combined with Red Hat's IPA (Identity Policy Audit) security information management solution to aid in the management of certificates. The certmonger service can be disabled with the following command:

$ sudo chkconfig certmonger off

Rationale:

The services provided by certmonger may be essential for systems fulfilling some roles a PKI infrastructure, but its functionality is not necessary for many other use cases.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27267-4

References:  11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7, PR.IP-1, PR.PT-3

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'certmonger' disable
/sbin/chkconfig --level 0123456 'certmonger' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service certmonger
  service:
    name: certmonger
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_certmonger_disabled
    - unknown_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-27267-4
    - NIST-800-53-CM-7
  

Rule   Disable Red Hat Network Service (rhnsd)   [ref]

The Red Hat Network service automatically queries Red Hat Network servers to determine whether there are any actions that should be executed, such as package updates. This only occurs if the system was registered to an RHN server or satellite and managed as such. The rhnsd service can be disabled with the following command:

$ sudo chkconfig rhnsd off

Rationale:

Although systems management and patching is extremely important to system security, management by a system outside the enterprise enclave is not desirable for some environments. However, if the system is being managed by RHN or RHN Satellite Server the rhnsd daemon can remain on.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-26846-6

References:  RHEL-06-000009, SV-50278r2_rule, SRG-OS-000096, 1.2.5, 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-000382, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, AC-17(8), CM-7, PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'rhnsd' disable
/sbin/chkconfig --level 0123456 'rhnsd' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service rhnsd
  service:
    name: rhnsd
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_rhnsd_disabled
    - unknown_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-26846-6
    - NIST-800-53-AC-17(8)
    - NIST-800-53-CM-7
    - DISA-STIG-RHEL-06-000009
  

Rule   Disable Software RAID Monitor (mdmonitor)   [ref]

The mdmonitor service is used for monitoring a software RAID array; hardware RAID setups do not use this service. The mdmonitor service can be disabled with the following command:

$ sudo chkconfig mdmonitor off

Rationale:

If software RAID monitoring is not required, there is no need to run this service.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27193-2

References:  11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7, PR.IP-1, PR.PT-3

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'mdmonitor' disable
/sbin/chkconfig --level 0123456 'mdmonitor' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service mdmonitor
  service:
    name: mdmonitor
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_mdmonitor_disabled
    - unknown_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-27193-2
    - NIST-800-53-CM-7
  

Rule   Enable IRQ Balance (irqbalance)   [ref]

The irqbalance service optimizes the balance between power savings and performance through distribution of hardware interrupts across multiple processors. The irqbalance service can be enabled with the following command:

$ sudo chkconfig --level 2345 irqbalance on

Rationale:

In an environment with multiple processors (now common), the irqbalance service provides potential speedups for handling interrupt requests.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-26990-2

References:  11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7, PR.IP-1, PR.PT-3

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'irqbalance' disable
/sbin/chkconfig --level 0123456 'irqbalance' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:enable
- name: Enable service irqbalance
  service:
    name: irqbalance
    enabled: "yes"
    state: "started"
  tags:
    - service_irqbalance_enabled
    - unknown_severity
    - enable_strategy
    - low_complexity
    - low_disruption
    - CCE-26990-2
    - NIST-800-53-CM-7
  when:  # Bare-metal/VM task, not applicable for containers
    - (ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker")

Rule   Disable Odd Job Daemon (oddjobd)   [ref]

The oddjobd service exists to provide an interface and access control mechanism through which specified privileged tasks can run tasks for unprivileged client applications. Communication with oddjobd through the system message bus. The oddjobd service can be disabled with the following command:

$ sudo chkconfig oddjobd off

Rationale:

The oddjobd service may provide necessary functionality in some environments, and can be disabled if it is not needed. Execution of tasks by privileged programs, on behalf of unprivileged ones, has traditionally been a source of privilege escalation security issues.

Severity: 
medium
Identifiers and References

Identifiers:  CCE-27257-5

References:  RHEL-06-000266, SV-50447r2_rule, SRG-OS-000096, 11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, CCI-000381, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7, PR.IP-1, PR.PT-3

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'oddjobd' disable
/sbin/chkconfig --level 0123456 'oddjobd' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service oddjobd
  service:
    name: oddjobd
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_oddjobd_disabled
    - medium_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-27257-5
    - NIST-800-53-CM-7
    - DISA-STIG-RHEL-06-000266
  

Rule   Disable Control Group Rules Engine (cgred)   [ref]

The cgred service moves tasks into control groups according to parameters set in the /etc/cgrules.conf configuration file. The cgred service can be disabled with the following command:

$ sudo chkconfig cgred off

Rationale:

Unless control groups are used to manage system resources, running the cgred service service is not necessary.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27252-6

References:  11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7, PR.IP-1, PR.PT-3

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'cgred' disable
/sbin/chkconfig --level 0123456 'cgred' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service cgred
  service:
    name: cgred
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_cgred_disabled
    - unknown_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-27252-6
    - NIST-800-53-CM-7
  

Rule   Disable SMART Disk Monitoring Service (smartd)   [ref]

SMART (Self-Monitoring, Analysis, and Reporting Technology) is a feature of hard drives that allows them to detect symptoms of disk failure and relay an appropriate warning. The smartd service can be disabled with the following command:

$ sudo chkconfig smartd off

Rationale:

SMART can help protect against denial of service due to failing hardware. Nevertheless, if it is not needed or the system's drives are not SMART-capable (such as solid state drives), it can be disabled.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-26853-2

References:  11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7, PR.IP-1, PR.PT-3

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'smartd' disable
/sbin/chkconfig --level 0123456 'smartd' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service smartd
  service:
    name: smartd
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_smartd_disabled
    - unknown_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-26853-2
    - NIST-800-53-CM-7
  

Rule   Disable Apache Qpid (qpidd)   [ref]

The qpidd service provides high speed, secure, guaranteed delivery services. It is an implementation of the Advanced Message Queuing Protocol. By default the qpidd service will bind to port 5672 and listen for connection attempts. The qpidd service can be disabled with the following command:

$ sudo chkconfig qpidd off

Rationale:

The qpidd service is automatically installed when the "base" package selection is selected during installation. The qpidd service listens for network connections, which increases the attack surface of the system. If the system is not intended to receive AMQP traffic, then the qpidd service is not needed and should be disabled or removed.

Severity: 
medium
Identifiers and References

Identifiers:  CCE-26928-2

References:  RHEL-06-000267, SV-50449r2_rule, SRG-OS-000096, 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-000382, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, AC-17(8), CM-7, PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'qpidd' disable
/sbin/chkconfig --level 0123456 'qpidd' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service qpidd
  service:
    name: qpidd
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_qpidd_disabled
    - medium_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-26928-2
    - NIST-800-53-AC-17(8)
    - NIST-800-53-CM-7
    - DISA-STIG-RHEL-06-000267
  

Rule   Disable Automatic Bug Reporting Tool (abrtd)   [ref]

The Automatic Bug Reporting Tool (abrtd) daemon collects and reports crash data when an application crash is detected. Using a variety of plugins, abrtd can email crash reports to system administrators, log crash reports to files, or forward crash reports to a centralized issue tracking system such as RHTSupport. The abrtd service can be disabled with the following command:

$ sudo chkconfig abrtd off

Rationale:

Mishandling crash data could expose sensitive information about vulnerabilities in software executing on the system, as well as sensitive information from within a process's address space or registers.

Severity: 
medium
Identifiers and References

Identifiers:  CCE-27247-6

References:  CCI-000381, RHEL-06-000261, SV-50441r2_rule, SRG-OS-000096, 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, AC-17(8), CM-7, PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'abrtd' disable
/sbin/chkconfig --level 0123456 'abrtd' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service abrtd
  service:
    name: abrtd
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_abrtd_disabled
    - medium_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-27247-6
    - NIST-800-53-AC-17(8)
    - NIST-800-53-CM-7
    - DISA-STIG-RHEL-06-000261
  

Rule   Disable Cyrus SASL Authentication Daemon (saslauthd)   [ref]

The saslauthd service handles plaintext authentication requests on behalf of the SASL library. The service isolates all code requiring superuser privileges for SASL authentication into a single process, and can also be used to provide proxy authentication services to clients that do not understand SASL based authentication. The saslauthd service can be disabled with the following command:

$ sudo chkconfig saslauthd off

Rationale:

The saslauthd service provides essential functionality for performing authentication in some directory environments, such as those which use Kerberos and LDAP. For others, however, in which only local files may be consulted, it is not necessary and should be disabled.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27263-3

References:  11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, AC-17(8), CM-7, PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'saslauthd' disable
/sbin/chkconfig --level 0123456 'saslauthd' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service saslauthd
  service:
    name: saslauthd
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_saslauthd_disabled
    - unknown_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-27263-3
    - NIST-800-53-AC-17(8)
    - NIST-800-53-CM-7
  

Rule   Disable Control Group Config (cgconfig)   [ref]

Control groups allow an administrator to allocate system resources (such as CPU, memory, network bandwidth, etc) among a defined group (or groups) of processes executing on a system. The cgconfig daemon starts at boot and establishes the predefined control groups. The cgconfig service can be disabled with the following command:

$ sudo chkconfig cgconfig off

Rationale:

Unless control groups are used to manage system resources, running the cgconfig service is not necessary.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27250-0

References:  11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7, PR.IP-1, PR.PT-3

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'cgconfig' disable
/sbin/chkconfig --level 0123456 'cgconfig' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service cgconfig
  service:
    name: cgconfig
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_cgconfig_disabled
    - unknown_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-27250-0
    - NIST-800-53-CM-7
  

Rule   Disable ntpdate Service (ntpdate)   [ref]

The ntpdate service sets the local hardware clock by polling NTP servers when the system boots. It synchronizes to the NTP servers listed in /etc/ntp/step-tickers or /etc/ntp.conf and then sets the local hardware clock to the newly synchronized system time. The ntpdate service can be disabled with the following command:

$ sudo chkconfig ntpdate off

Rationale:

The ntpdate service may only be suitable for systems which are rebooted frequently enough that clock drift does not cause problems between reboots. In any event, the functionality of the ntpdate service is now available in the ntpd program and should be considered deprecated.

Severity: 
medium
Identifiers and References

Identifiers:  CCE-27256-7

References:  RHEL-06-000265, SV-50445r2_rule, SRG-OS-000096, 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-000382, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, AC-17(8), CM-7, PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'ntpdate' disable
/sbin/chkconfig --level 0123456 'ntpdate' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service ntpdate
  service:
    name: ntpdate
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_ntpdate_disabled
    - medium_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-27256-7
    - NIST-800-53-AC-17(8)
    - NIST-800-53-CM-7
    - DISA-STIG-RHEL-06-000265
  

Rule   Disable Network Router Discovery Daemon (rdisc)   [ref]

The rdisc service implements the client side of the ICMP Internet Router Discovery Protocol (IRDP), which allows discovery of routers on the local subnet. If a router is discovered then the local routing table is updated with a corresponding default route. By default this daemon is disabled. The rdisc service can be disabled with the following command:

$ sudo chkconfig rdisc off

Rationale:

General-purpose systems typically have their network and routing information configured statically by a system administrator. Workstations or some special-purpose systems often use DHCP (instead of IRDP) to retrieve dynamic network configuration information.

Severity: 
medium
Identifiers and References

Identifiers:  CCE-27261-7

References:  RHEL-06-000268, SV-50451r2_rule, SRG-OS-000096, 1, 11, 12, 13, 14, 15, 16, 18, 3, 4, 6, 8, 9, APO01.06, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS01.05, DSS03.01, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, CCI-000382, 4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.11.2.6, A.12.1.1, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, AC-17(8), AC-4, CM-7, DE.AE-1, ID.AM-3, PR.AC-3, PR.AC-5, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'rdisc' disable
/sbin/chkconfig --level 0123456 'rdisc' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service rdisc
  service:
    name: rdisc
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_rdisc_disabled
    - medium_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-27261-7
    - NIST-800-53-AC-17(8)
    - NIST-800-53-AC-4
    - NIST-800-53-CM-7
    - DISA-STIG-RHEL-06-000268
  

Rule   Disable Red Hat Subscription Manager Daemon (rhsmcertd)   [ref]

The Red Hat Subscription Manager (rhsmcertd) periodically checks for changes in the entitlement certificates for a registered system and updates it accordingly. The rhsmcertd service can be disabled with the following command:

$ sudo chkconfig rhsmcertd off

Rationale:

The rhsmcertd service can provide administrators with some additional control over which of their systems are entitled to particular subscriptions. However, for systems that are managed locally or which are not expected to require remote changes to their subscription status, it is unnecessary and can be disabled.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27262-5

References:  11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7, PR.IP-1, PR.PT-3

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'rhsmcertd' disable
/sbin/chkconfig --level 0123456 'rhsmcertd' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service rhsmcertd
  service:
    name: rhsmcertd
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_rhsmcertd_disabled
    - unknown_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-27262-5
    - NIST-800-53-CM-7
  

Rule   Disable Portreserve (portreserve)   [ref]

The portreserve service is a TCP port reservation utility that can be used to prevent portmap from binding to well known TCP ports that are required for other services. The portreserve service can be disabled with the following command:

$ sudo chkconfig portreserve off

Rationale:

The portreserve service provides helpful functionality by preventing conflicting usage of ports in the reserved port range, but it can be disabled if not needed.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27258-3

References:  11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, AC-17(8), CM-7, PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'portreserve' disable
/sbin/chkconfig --level 0123456 'portreserve' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service portreserve
  service:
    name: portreserve
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_portreserve_disabled
    - unknown_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-27258-3
    - NIST-800-53-AC-17(8)
    - NIST-800-53-CM-7
  

Rule   Disable System Statistics Reset Service (sysstat)   [ref]

The sysstat service resets various I/O and CPU performance statistics to zero in order to begin counting from a fresh state at boot time. The sysstat service can be disabled with the following command:

$ sudo chkconfig sysstat off

Rationale:

By default the sysstat service merely runs a program at boot to reset the statistics, which can be retrieved using programs such as sar and sadc. These may provide useful insight into system operation, but unless used this service can be disabled.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27265-8

References:  11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7, PR.IP-1, PR.PT-3

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'sysstat' disable
/sbin/chkconfig --level 0123456 'sysstat' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service sysstat
  service:
    name: sysstat
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_sysstat_disabled
    - unknown_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-27265-8
    - NIST-800-53-CM-7
  
Group   Proxy Server   Group contains 1 group and 2 rules

[ref]   A proxy server is a very desirable target for a potential adversary because much (or all) sensitive data for a given infrastructure may flow through it. Therefore, if one is required, the system acting as a proxy server should be dedicated to that purpose alone and be stored in a physically secure location. The system's default proxy server software is Squid, and provided in an RPM package of the same name.

Group   Disable Squid if Possible   Group contains 2 rules

[ref]   If Squid was installed and activated, but the system does not need to act as a proxy server, then it should be disabled and removed.

Rule   Disable Squid   [ref]

The squid service can be disabled with the following command:

$ sudo chkconfig squid off

Rationale:

Running proxy server software provides a network-based avenue of attack, and should be removed if not needed.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27146-0

References:  2.2.13

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'squid' disable
/sbin/chkconfig --level 0123456 'squid' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service squid
  service:
    name: squid
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_squid_disabled
    - unknown_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-27146-0
  

Rule   Uninstall squid Package   [ref]

The squid package can be removed with the following command:

 $ sudo yum erase squid

Rationale:

If there is no need to make the proxy server software available, removing it provides a safeguard against its activation.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-26977-9

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:disable
# Function to remove packages on RHEL, Fedora, Debian, and possibly other systems.
#
# Example Call(s):
#
#     package_remove telnet-server
#
function package_remove {

# Load function arguments into local variables
local package="$1"

# Check sanity of the input
if [ $# -ne "1" ]
then
  echo "Usage: package_remove 'package_name'"
  echo "Aborting."
  exit 1
fi

if which dnf ; then
  if rpm -q --quiet "$package"; then
    dnf remove -y "$package"
  fi
elif which yum ; then
  if rpm -q --quiet "$package"; then
    yum remove -y "$package"
  fi
elif which apt-get ; then
  apt-get remove -y "$package"
else
  echo "Failed to detect available packaging system, tried dnf, yum and apt-get!"
  echo "Aborting."
  exit 1
fi

}

package_remove squid
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Ensure squid is removed
  package:
    name: squid
    state: absent
  tags:
    - package_squid_removed
    - unknown_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-26977-9
  
Remediation Puppet snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
include remove_squid

class remove_squid {
  package { 'squid':
    ensure => 'purged',
  }
}
Remediation Anaconda snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable

package --remove=squid
Group   DHCP   Group contains 2 groups and 6 rules

[ref]   The Dynamic Host Configuration Protocol (DHCP) allows systems to request and obtain an IP address and other configuration parameters from a server.

This guide recommends configuring networking on clients by manually editing the appropriate files under /etc/sysconfig. Use of DHCP can make client systems vulnerable to compromise by rogue DHCP servers, and should be avoided unless necessary. If using DHCP is necessary, however, there are best practices that should be followed to minimize security risk.

Group   Disable DHCP Client   Group contains 1 rule

[ref]   DHCP is the default network configuration method provided by the system installer, and common on many networks. Nevertheless, manual management of IP addresses for systems implies a greater degree of management and accountability for network activity.

Rule   Disable DHCP Client in ifcfg   [ref]

For each interface on the system (e.g. eth0), edit /etc/sysconfig/network-scripts/ifcfg-interface and make the following changes:

  • Correct the BOOTPROTO line to read:
    BOOTPROTO=none
  • Add or correct the following lines, substituting the appropriate values based on your site's addressing scheme:
    NETMASK=255.255.255.0
    IPADDR=192.168.1.2
    GATEWAY=192.168.1.1

Rationale:

DHCP relies on trusting the local network. If the local network is not trusted, then it should not be used. However, the automatic configuration provided by DHCP is commonly used and the alternative, manual configuration, presents an unacceptable burden in many circumstances.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27021-5

References:  RHEL-06-000292, SV-50480r3_rule, SRG-OS-999999, 11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, CCI-000366, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7, PR.IP-1, PR.PT-3

Group   Configure DHCP Server   Group contains 5 rules

[ref]   If the system must act as a DHCP server, the configuration information it serves should be minimized. Also, support for other protocols and DNS-updating schemes should be explicitly disabled unless needed. The configuration file for dhcpd is called /etc/dhcp/dhcpd.conf. The file begins with a number of global configuration options. The remainder of the file is divided into sections, one for each block of addresses offered by dhcpd, each of which contains configuration options specific to that address block.

Rule   Minimize Served Information   [ref]

Edit /etc/dhcp/dhcpd.conf. Examine each address range section within the file, and ensure that the following options are not defined unless there is an operational need to provide this information via DHCP:

option domain-name
option domain-name-servers
option nis-domain
option nis-servers
option ntp-servers
option routers
option time-offset

Warning:  By default, the Red Hat Enterprise Linux client installation uses DHCP to request much of the above information from the DHCP server. In particular, domain-name, domain-name-servers, and routers are configured via DHCP. These settings are typically necessary for proper network functionality, but are also usually static across systems at a given site.
Rationale:

Because the configuration information provided by the DHCP server could be maliciously provided to clients by a rogue DHCP server, the amount of information provided via DHCP should be minimized. Remove these definitions from the DHCP server configuration to ensure that legitimate clients do not unnecessarily rely on DHCP for this information.

Severity: 
unknown
Identifiers and References

References:  11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7, PR.IP-1, PR.PT-3

Rule   Deny BOOTP Queries   [ref]

Unless your network needs to support older BOOTP clients, disable support for the bootp protocol by adding or correcting the global option:

deny bootp;

Rationale:

The bootp option tells dhcpd to respond to BOOTP queries. If support for this simpler protocol is not needed, it should be disabled to remove attack vectors against the DHCP server.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27077-7

References:  11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7, PR.IP-1, PR.PT-3

Rule   Do Not Use Dynamic DNS   [ref]

To prevent the DHCP server from receiving DNS information from clients, edit /etc/dhcp/dhcpd.conf, and add or correct the following global option:

ddns-update-style none;

Warning:  The ddns-update-style option controls only whether the DHCP server will attempt to act as a Dynamic DNS client. As long as the DNS server itself is correctly configured to reject DDNS attempts, an incorrect ddns-update-style setting on the client is harmless (but should be fixed as a best practice).
Rationale:

The Dynamic DNS protocol is used to remotely update the data served by a DNS server. DHCP servers can use Dynamic DNS to publish information about their clients. This setup carries security risks, and its use is not recommended. If Dynamic DNS must be used despite the risks it poses, it is critical that Dynamic DNS transactions be protected using TSIG or some other cryptographic authentication mechanism. See dhcpd.conf(5) for more information about protecting the DHCP server from passing along malicious DNS data from its clients.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27049-6

References:  11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7, PR.IP-1, PR.PT-3

Rule   Deny Decline Messages   [ref]

Edit /etc/dhcp/dhcpd.conf and add or correct the following global option to prevent the DHCP server from responding the DHCPDECLINE messages, if possible:

deny declines;

Rationale:

The DHCPDECLINE message can be sent by a DHCP client to indicate that it does not consider the lease offered by the server to be valid. By issuing many DHCPDECLINE messages, a malicious client can exhaust the DHCP server's pool of IP addresses, causing the DHCP server to forget old address allocations.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27106-4

References:  11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7, PR.IP-1, PR.PT-3

Rule   Configure Logging   [ref]

Ensure that the following line exists in /etc/rsyslog.conf:

daemon.*           /var/log/daemon.log
Configure logwatch or other log monitoring tools to summarize error conditions reported by the dhcpd process.

Rationale:

By default, dhcpd logs notices to the daemon facility. Sending all daemon messages to a dedicated log file is part of the syslog configuration outlined in the Logging and Auditing section

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-26898-7

References:  1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-12, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1

Group   IMAP and POP3 Server   Group contains 3 groups and 5 rules

[ref]   Dovecot provides IMAP and POP3 services. It is not installed by default. The project page at http://www.dovecot.org contains more detailed information about Dovecot configuration.

Group   Configure Dovecot if Necessary   Group contains 1 group and 3 rules

[ref]   If the system will operate as an IMAP or POP3 server, the dovecot software should be configured securely by following the recommendations below.

Group   Enable SSL Support   Group contains 3 rules

[ref]   SSL should be used to encrypt network traffic between the Dovecot server and its clients. Users must authenticate to the Dovecot server in order to read their mail, and passwords should never be transmitted in clear text. In addition, protecting mail as it is downloaded is a privacy measure, and clients may use SSL certificates to authenticate the server, preventing another system from impersonating the server.

Rule   Configure Dovecot to Use the SSL Key file   [ref]

This option tells Dovecot where to find the the mail server's SSL Key.

Edit /etc/dovecot/conf.d/10-ssl.conf and add or correct the following line (note: the path below is the default path set by the Dovecot installation. If you are using a different path, ensure you reference the appropriate file):

ssl_key = </etc/pki/dovecot/private/dovecot.pem

Rationale:

SSL certificates are used by the client to authenticate the identity of the server, as well as to encrypt credentials and message traffic. Not using SSL to encrypt mail server traffic could allow unauthorized access to credentials and mail messages since they are sent in plain text over the network.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27633-7

Rule   Enable the SSL flag in /etc/dovecot.conf   [ref]

To allow clients to make encrypted connections the ssl flag in Dovecot's configuration file needs to be set to yes.

Edit /etc/dovecot/conf.d/10-ssl.conf and add or correct the following line:

ssl = yes

Rationale:

SSL encrypt network traffic between the Dovecot server and its clients protecting user credentials, mail as it is downloaded, and clients may use SSL certificates to authenticate the server, preventing another system from impersonating the server.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27571-9

Rule   Configure Dovecot to Use the SSL Certificate file   [ref]

This option tells Dovecot where to find the the mail server's SSL Certificate.

Edit /etc/dovecot/conf.d/10-ssl.conf and add or correct the following line (note: the path below is the default path set by the Dovecot installation. If you are using a different path, ensure you reference the appropriate file):

ssl_cert = </etc/pki/dovecot/certs/dovecot.pem
"

Rationale:

SSL certificates are used by the client to authenticate the identity of the server, as well as to encrypt credentials and message traffic. Not using SSL to encrypt mail server traffic could allow unauthorized access to credentials and mail messages since they are sent in plain text over the network.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27459-7

Group   Disable Dovecot   Group contains 2 rules

[ref]   If the system does not need to operate as an IMAP or POP3 server, the dovecot software should be disabled and removed.

Rule   Uninstall dovecot Package   [ref]

The dovecot package can be removed with the following command:

$ sudo yum erase dovecot

Rationale:

If there is no need to make the Dovecot software available, removing it provides a safeguard against its activation.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27039-7

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:disable
# Function to remove packages on RHEL, Fedora, Debian, and possibly other systems.
#
# Example Call(s):
#
#     package_remove telnet-server
#
function package_remove {

# Load function arguments into local variables
local package="$1"

# Check sanity of the input
if [ $# -ne "1" ]
then
  echo "Usage: package_remove 'package_name'"
  echo "Aborting."
  exit 1
fi

if which dnf ; then
  if rpm -q --quiet "$package"; then
    dnf remove -y "$package"
  fi
elif which yum ; then
  if rpm -q --quiet "$package"; then
    yum remove -y "$package"
  fi
elif which apt-get ; then
  apt-get remove -y "$package"
else
  echo "Failed to detect available packaging system, tried dnf, yum and apt-get!"
  echo "Aborting."
  exit 1
fi

}

package_remove dovecot
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Ensure dovecot is removed
  package:
    name: dovecot
    state: absent
  tags:
    - package_dovecot_removed
    - unknown_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-27039-7
  
Remediation Puppet snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
include remove_dovecot

class remove_dovecot {
  package { 'dovecot':
    ensure => 'purged',
  }
}
Remediation Anaconda snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable

package --remove=dovecot

Rule   Disable Dovecot Service   [ref]

The dovecot service can be disabled with the following command:

$ sudo chkconfig dovecot off

Rationale:

Running an IMAP or POP3 server provides a network-based avenue of attack, and should be disabled if not needed.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-26922-5

References:  2.2.11

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'dovecot' disable
/sbin/chkconfig --level 0123456 'dovecot' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service dovecot
  service:
    name: dovecot
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_dovecot_disabled
    - unknown_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-26922-5
  
Group   NFS and RPC   Group contains 9 groups and 16 rules

[ref]   The Network File System is a popular distributed filesystem for the Unix environment, and is very widely deployed. This section discusses the circumstances under which it is possible to disable NFS and its dependencies, and then details steps which should be taken to secure NFS's configuration. This section is relevant to systems operating as NFS clients, as well as to those operating as NFS servers.

Group   Configure NFS Servers   Group contains 3 rules

[ref]   The steps in this section are appropriate for systems which operate as NFS servers.

Rule   Use Root-Squashing on All Exports   [ref]

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.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27138-7

Rule   Restrict NFS Clients to Privileged Ports   [ref]

By default, the server NFS implementation requires that all client requests be made from ports less than 1024. If your organization has control over systems 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.

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27121-3

References:  11, 12, 14, 15, 16, 18, 3, 5, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.03, DSS06.06, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, AC-3, PR.AC-4, PR.AC-6, PR.PT-3

Rule   Ensure Insecure File Locking is Not Allowed   [ref]

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.

Severity: 
medium
Identifiers and References

Identifiers:  CCE-27167-6

References:  SRG-OS-000104, RHEL-06-000309, SV-50478r1_rule, CCI-000764

Group   Disable All NFS Services if Possible   Group contains 2 groups and 4 rules

[ref]   If there is not a reason for the system to operate as either an NFS client or an NFS server, follow all instructions in this section to disable subsystems required by NFS.

Warning:  The steps in this section will prevent a system from operating as either an NFS client or an NFS server. Only perform these steps on systems which do not need NFS at all.
Group   Disable Services Used Only by NFS   Group contains 3 rules

[ref]   If NFS is not needed, disable the NFS client daemons nfslock, rpcgssd, and rpcidmapd.

All of these daemons run with elevated privileges, and many listen for network connections. If they are not needed, they should be disabled to improve system security posture.

Rule   Disable Network File System Lock Service (nfslock)   [ref]

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 system is not configured to mount NFS filesystems then this service should be disabled. The nfslock service can be disabled with the following command:

$ sudo chkconfig nfslock off

Rationale:

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-27104-9

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'nfslock' disable
/sbin/chkconfig --level 0123456 'nfslock' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service nfslock
  service:
    name: nfslock
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_nfslock_disabled
    - unknown_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-27104-9
  

Rule   Disable RPC ID Mapping Service (rpcidmapd)   [ref]

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 chkconfig rpcidmapd off

Rationale:

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-26870-6

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'rpcidmapd' disable
/sbin/chkconfig --level 0123456 'rpcidmapd' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service rpcidmapd
  service:
    name: rpcidmapd
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_rpcidmapd_disabled
    - unknown_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-26870-6
  

Rule   Disable Secure RPC Client Service (rpcgssd)   [ref]

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 chkconfig rpcgssd off

Rationale:

Severity: 
unknown
Identifiers and References

Identifiers:  CCE-26864-9

Remediation Shell script:   (show)

Complexity:low
Disruption:low
Strategy:enable

/sbin/service 'rpcgssd' disable
/sbin/chkconfig --level 0123456 'rpcgssd' off
Remediation Ansible snippet:   (show)

Complexity:low
Disruption:low
Strategy:disable
- name: Disable service rpcgssd
  service:
    name: rpcgssd
    enabled: "no"
    state: "stopped"
  register: service_result
  failed_when: "service_result is failed and ('Could not find the requested service' not in service_result.msg)"
  tags:
    - service_rpcgssd_disabled
    - unknown_severity
    - disable_strategy
    - low_complexity
    - low_disruption
    - CCE-26864-9
  
Group   Disable netfs if Possible   Group contains 1 rule

[ref]   To determine if any network filesystems handled by netfs are currently mounted on the system execute the following command:

$ mount -t nfs,nfs4,smbfs,cifs,ncpfs
If the command did not return any output then disable netfs.

Rule   Disable Network File Systems (netfs)