RHEL 9 must mount /dev/shm with the nosuid option.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-257865 | RHEL-09-231120 | SV-257865r1044946_rule | CCI-001764 | medium |
| Description | ||||
| 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. | ||||
| STIG | Date | |||
| Red Hat Enterprise Linux 9 Security Technical Implementation Guide | 2025-05-14 | |||
Details
Check Text (C-257865r1044946_chk)
Verify "/dev/shm" is mounted with the "nosuid" 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 "nosuid" option, this is a finding.
Fix Text (F-61530r925581_fix)
Modify "/etc/fstab" to use the "nosuid" option on the "/dev/shm" file system.