Guide to the Secure Configuration of Red Hat Enterprise Linux 9
Rules, Groups, and Values defined within the XCCDF Benchmark
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Install sudo Package
Thesudo
package can be installed with the following command:$ sudo dnf install sudo
Rule Medium Severity -
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 -
maxrepeat
Maximum Number of Consecutive Repeating Characters in a PasswordValue -
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 -
Ensure Users Re-Authenticate for Privilege Escalation - sudo NOPASSWD
The sudo <code>NOPASSWD</code> tag, when specified, allows a user to execute commands using sudo without having to authenticate. This should be disabled by making sure that the <code>NOPASSWD</code...Rule Medium Severity -
Require Re-Authentication When Using the sudo Command
The sudo <code>timestamp_timeout</code> tag sets the amount of time sudo password prompt waits. The default <code>timestamp_timeout</code> value is 5 minutes. The timestamp_timeout should be config...Rule Medium Severity -
The operating system must restrict privilege elevation to authorized personnel
The sudo command allows a user to execute programs with elevated (administrator) privileges. It prompts the user for their password and confirms your request to execute a command by checking a file...Rule Medium Severity -
Only the VDSM User Can Use sudo NOPASSWD
The sudo <code>NOPASSWD</code> tag, when specified, allows a user to execute commands using sudo without having to authenticate. Only the <code>vdsm</code> user should have this capability in any s...Rule Medium Severity -
Ensure sudo only includes the default configuration directory
Administrators can configure authorized <code>sudo</code> users via drop-in files, and it is possible to include other directories and configuration files from the file currently being parsed. Mak...Rule Medium Severity -
minclass
Minimum number of categories of characters that must exist in a passwordValue -
minlen
Minimum number of characters in passwordValue -
Configure dnf-automatic to Install Only Security Updates
To configure <code>dnf-automatic</code> to install only security updates automatically, set <code>upgrade_type</code> to <code>security</code> under <code>[commands]</code> section in <code>/etc/dn...Rule Low Severity -
ocredit
Minimum number of other (special characters) in passwordValue -
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 -
Ensure invoking users password for privilege escalation when using sudo
The sudoers security policy requires that users authenticate themselves before they can use sudo. When sudoers requires authentication, it validates the invoking user's credentials. The expected ou...Rule Medium Severity -
System Tooling / Utilities
The following checks evaluate the system for recommended base packages -- both for installation and removal.Group -
Ensure gnutls-utils is installed
Thegnutls-utils
package can be installed with the following command:$ sudo dnf install gnutls-utils
Rule Medium Severity -
Ensure nss-tools is installed
Thenss-tools
package can be installed with the following command:$ sudo dnf install nss-tools
Rule Medium Severity -
Install openscap-scanner Package
Theopenscap-scanner
package can be installed with the following command:$ sudo dnf install openscap-scanner
Rule Medium Severity -
Install rear Package
Therear
package can be installed with the following command:$ sudo dnf install rear
Rule Medium Severity -
Install rng-tools Package
Therng-tools
package can be installed with the following command:$ sudo dnf install rng-tools
Rule Low Severity -
An SELinux Context must be configured for the pam_faillock.so records directory
Thedir
configuration option in PAM pam_faillock.so module defines where the lockout records is stored. The configured directory must have the correct SELinux context.Rule Medium Severity -
Install subscription-manager Package
Thesubscription-manager
package can be installed with the following command:$ sudo dnf install subscription-manager
Rule Medium Severity -
Uninstall geolite2-city Package
Thegeolite2-city
package can be removed with the following command:$ sudo dnf erase geolite2-city
Rule Low Severity -
Uninstall geolite2-country Package
Thegeolite2-country
package can be removed with the following command:$ sudo dnf erase geolite2-country
Rule Low Severity -
Uninstall gssproxy Package
Thegssproxy
package can be removed with the following command:$ sudo dnf erase gssproxy
Rule Medium Severity -
Uninstall iprutils Package
Theiprutils
package can be removed with the following command:$ sudo dnf erase iprutils
Rule Medium Severity -
Uninstall krb5-workstation Package
Thekrb5-workstation
package can be removed with the following command:$ sudo dnf erase krb5-workstation
Rule Medium Severity -
Uninstall tuned Package
Thetuned
package can be removed with the following command:$ sudo dnf erase tuned
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 -
Install dnf-automatic Package
Thednf-automatic
package can be installed with the following command:$ sudo dnf install dnf-automatic
Rule Medium Severity -
Ensure dnf Removes Previous Package Versions
<code>dnf</code> should be configured to remove previous software components after new versions have been installed. To configure <code>dnf</code> to remove the previous software components after ...Rule Low Severity -
Configure dnf-automatic to Install Available Updates Automatically
To ensure that the packages comprising the available updates will be automatically installed by <code>dnf-automatic</code>, set <code>apply_updates</code> to <code>yes</code> under <code>[commands]...Rule Medium Severity -
retry
Number of retry attempts before erroring outValue -
Ensure gpgcheck Enabled for Local Packages
<code>dnf</code> should be configured to verify the signature(s) of local packages prior to installation. To configure <code>dnf</code> to verify signatures of local packages, set the <code>localpk...Rule High Severity -
Ensure gpgcheck Enabled for All dnf Package Repositories
To ensure signature checking is not disabled for any repos, remove any lines from files in/etc/yum.repos.d
of the form:gpgcheck=0
Rule High Severity -
Ensure Software Patches Installed
If the system is joined to the Red Hat Network, a Red Hat Satellite Server, or a yum server, run the following command to install updates: <pre>$ sudo yum update</pre> If the system is not configu...Rule Medium Severity -
Enable dnf-automatic Timer
Thednf-automatic
timer can be enabled with the following command:$ sudo systemctl enable dnf-automatic.timer
Rule Medium Severity -
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 -
Authselect profile
Specify the authselect profile to selectValue -
Enable authselect
Configure user authentication setup to use the <code>authselect</code> tool. If authselect profile is selected, the rule will enable the <xccdf-1.2:sub idref="xccdf_org.ssgproject.content_value_var...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 -
Account Lockouts Must Be Logged
PAM faillock locks an account due to excessive password failures, this event must be logged.Rule Medium Severity -
ucredit
Minimum number of upper case in passwordValue -
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 -
MotD 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 -
Remote 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 Login Banner for Remote Connections
To configure the system login banner edit <code>/etc/issue.net</code>. Replace the default text with a message compliant with the local site policy or a legal disclaimer. The DoD required text is ...Rule Medium Severity
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