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

STIG ID: RHEL-09-231110  |  SRG: SRG-OS-000368-GPOS-00154 | Severity: medium |  CCI: CCI-001764

Vulnerability 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.

Check

Verify "/dev/shm" is mounted with the "nodev" option with the following command:

$ mount | grep /dev/shm

tmpfs on /dev/shm type tmpfs (rw,nodev,nosuid,noexec,seclabel)

If the /dev/shm file system is mounted without the "nodev" option, this is a finding.

Fix

Modify "/etc/fstab" to use the "nodev" option on the "/dev/shm" file system.