Finding ID | Version | Rule ID | IA Controls | Severity |
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V-257816 | RHEL-09-213105 | SV-257816r991589_rule | Medium |
Description |
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User namespaces are used primarily for Linux containers. The value "0" disallows the use of user namespaces. |
STIG | Date |
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Red Hat Enterprise Linux 9 Security Technical Implementation Guide | 2024-06-04 |
Check Text ( C-61557r942980_chk ) |
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Verify RHEL 9 disables the use of user namespaces with the following commands: Note: User namespaces are used primarily for Linux containers. If containers are in use, this requirement is Not Applicable. $ sudo sysctl user.max_user_namespaces user.max_user_namespaces = 0 If the returned line does not have a value of "0", or a line is not returned, this is a finding. Check that the configuration files are present to enable this kernel parameter. $ sudo /usr/lib/systemd/systemd-sysctl --cat-config | egrep -v '^(#|;)' | grep -F user.max_user_namespaces | tail -1 user.max_user_namespaces = 0 If the network parameter "user.max_user_namespaces" is not equal to "0", or nothing is returned, this is a finding. |
Fix Text (F-61481r925434_fix) |
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Configure RHEL 9 to disable the use of user namespaces by adding the following line to a file, in the "/etc/sysctl.d" directory: Note: User namespaces are used primarily for Linux containers. If containers are in use, this requirement is Not Applicable. user.max_user_namespaces = 0 The system configuration files need to be reloaded for the changes to take effect. To reload the contents of the files, run the following command: $ sudo sysctl --system |