AlmaLinux OS 9 must prevent files with the setuid and setgid bit set from being executed on file systems that contain user home directories.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-269309	ALMA-09-025980	SV-269309r1050191_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. Satisfies: SRG-OS-000480-GPOS-00230, SRG-OS-000368-GPOS-00154

STIG	Date
CloudLinux AlmaLinux OS 9 Security Technical Implementation Guide	2025-05-22

Details

Check Text (C-73340r1048303_chk)

Verify "/home" is mounted with the "nosuid" option with the following command:

Note: If a separate file system has not been created for the user home directories (user home directories are mounted under "/"), this is automatically a finding, as the "nosuid" option cannot be used on the "/" system.

$ mount | grep /home

/dev/mapper/luks-10a20c46-483d-4d12-831f-5328eda18fd1 on /home type xfs (rw,nosuid,nodev,relatime,seclabel,attr2,inode64,logbufs=8,logbsize=32k,noquota)

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

Fix Text (F-73241r1048304_fix)

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