SLEM 5 file systems that contain user home directories must be mounted to prevent files with the setuid and setgid bit set from being executed.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-261285	SLEM-05-231045	SV-261285r996838_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 unprivileged users to attain unauthorized administrative access.

STIG	Date
SUSE Linux Enterprise Micro (SLEM) 5 Security Technical Implementation Guide	2024-06-04

Details

Check Text ( C-65014r996838_chk )
Verify that SLEM 5 file systems that contain user home directories are mounted with the "nosuid" option. Print the currently active file system mount options of the file system(s) that contain the user home directories with the following command: > for X in `awk -F: '($3>=1000)&&($7 !~ /nologin/){print $6}' /etc/passwd`; do findmnt -nkT $X; done \| sort -r /home /dev/mapper/system-home ext4 rw,nosuid,realtime,data=ordered If a file system containing user home directories is not mounted with the FSTYPE OPTION nosuid, this is a finding. Note: If a separate file system has not been created for the user home directories (user home directories are mounted under "/"), this is not a finding as the "nosuid" option cannot be used on the "/" system.

Check Text ( C-65014r996838_chk )

Verify that SLEM 5 file systems that contain user home directories are mounted with the "nosuid" option.

Print the currently active file system mount options of the file system(s) that contain the user home directories with the following command:

> for X in `awk -F: '($3>=1000)&&($7 !~ /nologin/){print $6}' /etc/passwd`; do findmnt -nkT $X; done | sort -r
/home /dev/mapper/system-home ext4 rw,nosuid,realtime,data=ordered

If a file system containing user home directories is not mounted with the FSTYPE OPTION nosuid, this is a finding.

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

Fix Text (F-64922r995721_fix)
Configure SLEM 5 "/etc/fstab" file to use the "nosuid" option on file systems that contain user home directories for interactive users. Remount the filesystems. > sudo mount -o remount /home