Title

RHEL 9 must mount /dev/shm with the nosuid option. (Cat II impact)

Discussion

The "nosuid" mount option causes the system to not execute "setuid" and "setgid" files with owner privileges. This option must be used for mounting any file system not containing approved "setuid" and "setguid" files. Executing files from untrusted file systems increases the opportunity for nonprivileged users to attain unauthorized administrative access.

Check Content

Verify "/dev/shm" is mounted with the "nosuid" option with the following command: $ findmnt /dev/shm /dev/shm tmpfs tmpfs rw,nodev,nosuid,noexec,seclabel If the mount options for /dev/shm does not include nosuid, this is a finding.

Fix Text

Configure "/dev/shm" to mount with the "nosuid" option. Modify "/etc/fstab" to use the "nosuid" option on the "/dev/shm" file system. To reload all implicit mount units and update the dependency graph so that new options will apply correctly at next remount, run the following command: $ sudo systemctl daemon-reload Use the following command to apply the changes immediately without a reboot: $ sudo mount -o remount /dev/shm

Additional Identifiers

Rule ID: SV-257865r1155636_rule

Vulnerability ID: V-257865

Group Title: SRG-OS-000368-GPOS-00154

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