Guide to the Secure Configuration of WRLinux 8
with profile Basic Profile for Embedded SystemsThis profile contains items common to many embedded Linux installations. Regardless of your system's deployment objective, all of these checks should pass.
The SCAP Security Guide Project
https://www.open-scap.org/security-policies/scap-security-guide
https://www.open-scap.org/security-policies/scap-security-guide
This guide presents a catalog of security-relevant
configuration settings for WRLinux 8. 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
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.
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 Title | Basic Profile for Embedded Systems |
|---|---|
| Profile ID | xccdf_org.ssgproject.content_profile_basic-embedded |
CPE Platforms
- cpe:/o:windriver:wrlinux:8
Revision History
Current version: 0.1.60
- draft (as of 2022-01-27)
Table of Contents
Checklist
| Group Guide to the Secure Configuration of WRLinux 8 Group contains 8 groups and 11 rules | ||||||||||||||||||||
| Group System Settings Group contains 7 groups and 11 rules | ||||||||||||||||||||
[ref]
Contains rules that check correct system settings. | ||||||||||||||||||||
| Group Account and Access Control Group contains 6 groups and 11 rules | ||||||||||||||||||||
[ref]
In traditional Unix security, if an attacker gains
shell access to a certain login account, they can perform any action
or access any file to which that account has access. Therefore,
making it more difficult for unauthorized people to gain shell
access to accounts, particularly to privileged accounts, is a
necessary part of securing a system. This section introduces
mechanisms for restricting access to accounts under
WRLinux 8. | ||||||||||||||||||||
| Group Protect Accounts by Restricting Password-Based Login Group contains 2 groups and 4 rules | ||||||||||||||||||||
[ref]
Conventionally, Unix shell accounts are accessed by
providing a username and password to a login program, which tests
these values for correctness using the /etc/passwd and
/etc/shadow files. Password-based login is vulnerable to
guessing of weak passwords, and to sniffing and man-in-the-middle
attacks against passwords entered over a network or at an insecure
console. Therefore, mechanisms for accessing accounts by entering
usernames and passwords should be restricted to those which are
operationally necessary. | ||||||||||||||||||||
| Group Verify Proper Storage and Existence of Password Hashes Group contains 3 rules | ||||||||||||||||||||
[ref]
By default, password hashes for local accounts are stored
in the second field (colon-separated) in
/etc/shadow. This file should be readable only by
processes running with root credentials, preventing users from
casually accessing others' password hashes and attempting
to crack them.
However, it remains possible to misconfigure the system
and store password hashes
in world-readable files such as /etc/passwd, or
to even store passwords themselves in plaintext on the system.
Using system-provided tools for password change/creation
should allow administrators to avoid such misconfiguration. | ||||||||||||||||||||
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| Group Restrict Root Logins Group contains 1 rule | ||||||||||||||||||||
[ref]
Direct root logins should be allowed only for emergency use.
In normal situations, the administrator should access the system
via a unique unprivileged account, and then use su or sudo to execute
privileged commands. Discouraging administrators from accessing the
root account directly ensures an audit trail in organizations with
multiple administrators. Locking down the channels through which
root can connect directly also reduces opportunities for
password-guessing against the root account. The login program
uses the file /etc/securetty to determine which interfaces
should allow root logins.
The virtual devices /dev/console
and /dev/tty* represent the system consoles (accessible via
the Ctrl-Alt-F1 through Ctrl-Alt-F6 keyboard sequences on a default
installation). The default securetty file also contains /dev/vc/*.
These are likely to be deprecated in most environments, but may be retained
for compatibility. Root should also be prohibited from connecting
via network protocols. Other sections of this document
include guidance describing how to prevent root from logging in via SSH. | ||||||||||||||||||||
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| Group Secure Session Configuration Files for Login Accounts Group contains 2 groups and 7 rules | ||||||||||||||||||||
[ref]
When a user logs into a Unix account, the system
configures the user's session by reading a number of files. Many of
these files are located in the user's home directory, and may have
weak permissions as a result of user error or misconfiguration. If
an attacker can modify or even read certain types of account
configuration information, they can often gain full access to the
affected user's account. Therefore, it is important to test and
correct configuration file permissions for interactive accounts,
particularly those of privileged users such as root or system
administrators. | ||||||||||||||||||||
| Group Ensure that No Dangerous Directories Exist in Root's Path Group contains 2 rules | ||||||||||||||||||||
[ref]
The active path of the root account can be obtained by
starting a new root shell and running:
# echo $PATHThis will produce a colon-separated list of directories in the path. Certain path elements could be considered dangerous, as they could lead to root executing unknown or untrusted programs, which could contain malicious code. Since root may sometimes work inside untrusted directories, the . character, which represents the
current directory, should never be in the root path, nor should any
directory which can be written to by an unprivileged or
semi-privileged (system) user.
It is a good practice for administrators to always execute privileged commands by typing the full path to the command. | ||||||||||||||||||||
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| Group Ensure that Users Have Sensible Umask Values Group contains 2 rules | ||||||||||||||||||||
[ref]
The umask setting controls the default permissions
for the creation of new files.
With a default umask setting of 077, files and directories
created by users will not be readable by any other user on the
system. Users who wish to make specific files group- or
world-readable can accomplish this by using the chmod command.
Additionally, users can make all their files readable to their
group by default by setting a umask of 027 in their shell
configuration files. If default per-user groups exist (that is, if
every user has a default group whose name is the same as that
user's username and whose only member is the user), then it may
even be safe for users to select a umask of 007, making it very
easy to intentionally share files with groups of which the user is
a member.
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