RHEL 9 must mount /var/tmp with the nosuid option.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-257878	RHEL-09-231185	SV-257878r958804_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-61619r925619_chk)

Verify "/var/tmp" is mounted with the "nosuid" option:

$ mount | grep /var/tmp

/dev/mapper/rhel-var-tmp on /var/tmp type xfs (rw,nodev,nosuid,noexec,seclabel)

If the "/var/tmp" file system is mounted without the "nosuid" option, this is a finding.

Fix Text (F-61543r925620_fix)

Modify "/etc/fstab" to use the "nosuid" option on the "/var/tmp" directory.