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RHEL-09-231110 RHEL 9 must mount /dev/shm with the nodev option.

DISA STIG library V2R10
All changes in this version
first version loaded CAT II

Maps to CM-7(2) via CCI-001764

Title

RHEL 9 must mount /dev/shm with the nodev option.

Control

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

Discussion

The "nodev" mount option causes the system to not interpret character or block special devices. Executing character or block special devices from untrusted file systems increases the opportunity for nonprivileged users to attain unauthorized administrative access. The only legitimate location for device files is the "/dev" directory located on the root partition, with the exception of chroot jails if implemented.

Related controls

CCI-001764

Fix

Configure "/dev/shm" to mount with the "nodev" option. Modify "/etc/fstab" to use the "nodev" 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