RHEL 9 must prevent files with the setuid and setgid bit set from being executed on file systems that are used with removable media.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-257859	RHEL-09-231090	SV-257859r991589_rule		Medium

Description

The "nosuid" mount option causes the system not to 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-61600r925562_chk)

Verify file systems that are used for removable media are mounted with the "nosuid" option with the following command:

$ more /etc/fstab

UUID=2bc871e4-e2a3-4f29-9ece-3be60c835222 /mnt/usbflash vfat noauto,owner,ro,nosuid,nodev,noexec 0 0

If a file system found in "/etc/fstab" refers to removable media and it does not have the "nosuid" option set, this is a finding.

Fix Text (F-61524r925563_fix)

Configure the "/etc/fstab" to use the "nosuid" option on file systems that are associated with removable media.