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		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	2024-12-04

Details

Check Text (C-61606r1044945_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.