RHEL 8 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-230299	RHEL-08-010570	SV-230299r627750_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 unprivileged users to attain unauthorized administrative access.

STIG	Date
Red Hat Enterprise Linux 8 Security Technical Implementation Guide	2021-12-03

Details

Check Text ( C-32968r567643_chk )
Verify file systems that contain user home directories are mounted with the "nosuid" option. 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. Find the file system(s) that contain the user home directories with the following command: $ sudo awk -F: '($3>=1000)&&($7 !~ /nologin/){print $1,$3,$6}' /etc/passwd smithj:1001: /home/smithj robinst:1002: /home/robinst Check the file systems that are mounted at boot time with the following command: $ sudo more /etc/fstab UUID=a411dc99-f2a1-4c87-9e05-184977be8539 /home xfs rw,relatime,discard,data=ordered,nosuid,nodev,noexec 0 0 If a file system found in "/etc/fstab" refers to the user home directory file system and it does not have the "nosuid" option set, this is a finding.

Check Text ( C-32968r567643_chk )

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

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.

Find the file system(s) that contain the user home directories with the following command:

$ sudo awk -F: '($3>=1000)&&($7 !~ /nologin/){print $1,$3,$6}' /etc/passwd

smithj:1001: /home/smithj
robinst:1002: /home/robinst

Check the file systems that are mounted at boot time with the following command:

$ sudo more /etc/fstab

UUID=a411dc99-f2a1-4c87-9e05-184977be8539 /home xfs rw,relatime,discard,data=ordered,nosuid,nodev,noexec 0 0

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

Fix Text (F-32943r567644_fix)
Configure the "/etc/fstab" to use the "nosuid" option on file systems that contain user home directories for interactive users.