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

STIG ID: RHEL-09-231185  |  SRG: SRG-OS-000368-GPOS-00154 | Severity: medium |  CCI: CCI-001764

Vulnerability Discussion

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.

Check

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

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