Guide to the Secure Configuration of OpenEmbedded
Rules, Groups, and Values defined within the XCCDF Benchmark
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Installing and Maintaining Software
The following sections contain information on security-relevant choices during the initial operating system installation process and the setup of software updates.Group -
Prefer to use a 64-bit Operating System when supported
Prefer installation of 64-bit operating systems when the CPU supports it.Rule Medium Severity -
System and Software Integrity
System and software integrity can be gained by installing antivirus, increasing system encryption strength with FIPS, verifying installed software, enabling SELinux, installing an Intrusion Prevent...Group -
Software Integrity Checking
Both the AIDE (Advanced Intrusion Detection Environment) software and the RPM package management system provide mechanisms for verifying the integrity of installed software. AIDE uses snapshots of ...Group -
fapolicyd Must be Configured to Limit Access to Users Home Folders
fapolicyd needs be configured so that users cannot give access to their home folders to other users.Rule Medium Severity -
System Cryptographic Policies
Linux has the capability to centrally configure cryptographic polices. The command <code>update-crypto-policies</code> is used to set the policy applicable for the various cryptographic back-ends, ...Group -
The system-provided crypto policies
Specify the crypto policy for the system.Value -
Configure System Cryptography Policy
To configure the system cryptography policy to use ciphers only from the <code><xccdf-1.2:sub idref="xccdf_org.ssgproject.content_value_var_system_crypto_policy" use="legacy"></xccdf-1.2:sub></code...Rule High Severity -
Harden SSH client Crypto Policy
Crypto Policies are means of enforcing certain cryptographic settings for selected applications including OpenSSH client. To override the system wide crypto policy for Openssh client, place a file ...Rule Medium Severity -
Ensure /dev/shm is configured
The <code>/dev/shm</code> is a traditional shared memory concept. One program will create a memory portion, which other processes (if permitted) can access. If <code>/dev/shm</code> is not configur...Rule Low Severity -
Ensure /home Located On Separate Partition
If user home directories will be stored locally, create a separate partition for <code>/home</code> at installation time (or migrate it later using LVM). If <code>/home</code> will be mounted from ...Rule Low Severity -
Ensure /srv Located On Separate Partition
If a file server (FTP, TFTP...) is hosted locally, create a separate partition for <code>/srv</code> at installation time (or migrate it later using LVM). If <code>/srv</code> will be mounted from ...Rule Unknown Severity -
Ensure /tmp Located On Separate Partition
The/tmp
directory is a world-writable directory used for temporary file storage. Ensure it has its own partition or logical volume at installation time, or migrate it using LVM.Rule Low Severity -
Ensure /var Located On Separate Partition
The <code>/var</code> directory is used by daemons and other system services to store frequently-changing data. Ensure that <code>/var</code> has its own partition or logical volume at installation...Rule Low Severity -
Ensure /var/log Located On Separate Partition
System logs are stored in the/var/log
directory. Ensure that/var/log
has its own partition or logical volume at installation time, or migrate it using LVM.Rule Low Severity -
Ensure /var/log/audit Located On Separate Partition
Audit logs are stored in the <code>/var/log/audit</code> directory. Ensure that <code>/var/log/audit</code> has its own partition or logical volume at installation time, or migrate it using LVM. M...Rule Low Severity -
GNOME Desktop Environment
GNOME is a graphical desktop environment bundled with many Linux distributions that allow users to easily interact with the operating system graphically rather than textually. The GNOME Graphical D...Group -
Sudo - logfile value
Specify the sudo logfile to use. The default value used here matches the example location from CIS, which uses /var/log/sudo.log.Value -
Ensure Privileged Escalated Commands Cannot Execute Other Commands - sudo NOEXEC
The sudo <code>NOEXEC</code> tag, when specified, prevents user executed commands from executing other commands, like a shell for example. This should be enabled by making sure that the <code>NOEXE...Rule High Severity -
Ensure Only Users Logged In To Real tty Can Execute Sudo - sudo requiretty
The sudo <code>requiretty</code> tag, when specified, will only execute sudo commands from users logged in to a real tty. This should be enabled by making sure that the <code>requiretty</code> tag ...Rule Medium Severity -
Ensure Only Users Logged In To Real tty Can Execute Sudo - sudo use_pty
The sudo <code>use_pty</code> tag, when specified, will only execute sudo commands from users logged in to a real tty. This should be enabled by making sure that the <code>use_pty</code> tag exists...Rule Medium Severity -
Ensure Sudo Logfile Exists - sudo logfile
A custom log sudo file can be configured with the 'logfile' tag. This rule configures a sudo custom logfile at the default location suggested by CIS, which uses /var/log/sudo.log.Rule Low Severity -
Don't define allowed commands in sudoers by means of exclusion
Policies applied by sudo through the sudoers file should not involve negation. Each user specification in the <code>sudoers</code> file contains a comma-delimited list of command specifications. T...Rule Medium Severity -
Don't target root user in the sudoers file
The targeted users of a user specification should be, as much as possible, non privileged users (i.e.: non-root). User specifications have to explicitly list the runas spec (i.e. the list of targe...Rule Medium Severity -
System Tooling / Utilities
The following checks evaluate the system for recommended base packages -- both for installation and removal.Group -
Ensure nss-tools is installed
Thenss-tools
package can be installed with the following command:$ sudo dnf install nss-tools
Rule Medium Severity -
Updating Software
The <code>dnf</code> command line tool is used to install and update software packages. The system also provides a graphical software update tool in the <b>System</b> menu, in the <b>Administration...Group -
Account and Access Control
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 mor...Group -
Warning Banners for System Accesses
Each system should expose as little information about itself as possible. <br> <br> System banners, which are typically displayed just before a login prompt, give out information about the s...Group -
Login Banner Verbiage
Enter an appropriate login banner for your organization. Please note that new lines must be expressed by the '\n' character and special characters like parentheses and quotation marks must be escap...Value -
Modify the System Message of the Day Banner
To configure the system message banner edit <code>/etc/motd</code>. Replace the default text with a message compliant with the local site policy or a legal disclaimer. The DoD required text is eit...Rule Medium Severity -
Verify Group Ownership of System Login Banner
To properly set the group owner of/etc/issue
, run the command:$ sudo chgrp root /etc/issue
Rule Medium Severity -
Verify Group Ownership of Message of the Day Banner
To properly set the group owner of/etc/motd
, run the command:$ sudo chgrp root /etc/motd
Rule Medium Severity -
Verify ownership of System Login Banner
To properly set the owner of/etc/issue
, run the command:$ sudo chown root /etc/issue
Rule Medium Severity -
Verify ownership of Message of the Day Banner
To properly set the owner of/etc/motd
, run the command:$ sudo chown root /etc/motd
Rule Medium Severity -
Verify permissions on System Login Banner
To properly set the permissions of/etc/issue
, run the command:$ sudo chmod 0644 /etc/issue
Rule Medium Severity -
Verify permissions on Message of the Day Banner
To properly set the permissions of/etc/motd
, run the command:$ sudo chmod 0644 /etc/motd
Rule Medium Severity -
Disallow Configuration to Bypass Password Requirements for Privilege Escalation
Verify the operating system is not configured to bypass password requirements for privilege escalation. Check the configuration of the "/etc/pam.d/sudo" file with the following command: <pre>$ sudo...Rule Medium Severity -
Ensure PAM Displays Last Logon/Access Notification
To configure the system to notify users of last logon/access using <code>pam_lastlog</code>, add or correct the <code>pam_lastlog</code> settings in <code>/etc/pam.d/postlogin</code> to include <co...Rule Low Severity -
Set Lockouts for Failed Password Attempts
The <code>pam_faillock</code> PAM module provides the capability to lock out user accounts after a number of failed login attempts. Its documentation is available in <code>/usr/share/doc/pam-VERSIO...Group -
pwhistory_remember
Prevent password re-use using password history lookupValue -
PAM pwhistory remember - control flag
'Specify the control flag required for password remember requirement. If multiple values are allowed write them separated by commas as in "required,requisite", for remediations the first value will...Value -
Account Lockouts Must Be Logged
PAM faillock locks an account due to excessive password failures, this event must be logged.Rule Medium Severity -
Limit Password Reuse: system-auth
Do not allow users to reuse recent passwords. This can be accomplished by using the <code>remember</code> option for the <code>pam_pwhistory</code> PAM module. <br> <br> On systems with n...Rule Medium Severity -
Account Lockouts Must Be Logged
PAM faillock locks an account due to excessive password failures, this event must be logged.Rule Medium Severity -
Set Password Quality Requirements
The default <code>pam_pwquality</code> PAM module provides strength checking for passwords. It performs a number of checks, such as making sure passwords are not similar to dictionary words, are of...Group -
Set Password Quality Requirements with pam_pwquality
The <code>pam_pwquality</code> PAM module can be configured to meet requirements for a variety of policies. <br> <br> For example, to configure <code>pam_pwquality</code> to require at lea...Group -
minclass
Minimum number of categories of characters that must exist in a passwordValue -
minlen
Minimum number of characters in passwordValue -
Ensure PAM Enforces Password Requirements - Minimum Length
The pam_pwquality module's <code>minlen</code> parameter controls requirements for minimum characters required in a password. Add <code>minlen=<xccdf-1.2:sub idref="xccdf_org.ssgproject.content_val...Rule Medium Severity
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