RHEL 8 must mount /dev/shm with the noexec option.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-230510	RHEL-08-040122	SV-230510r854051_rule		Medium

Description
The organization must identify authorized software programs and permit execution of authorized software. The process used to identify software programs that are authorized to execute on organizational information systems is commonly referred to as whitelisting. The "noexec" mount option causes the system to not execute binary files. This option must be used for mounting any file system not containing approved binary files, as they may be incompatible. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. The "nodev" mount option causes the system to not interpret character or block special devices. Executing character or block special devices from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. 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.

Description

The organization must identify authorized software programs and permit execution of authorized software. The process used to identify software programs that are authorized to execute on organizational information systems is commonly referred to as whitelisting. The "noexec" mount option causes the system to not execute binary files. This option must be used for mounting any file system not containing approved binary files, as they may be incompatible. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. The "nodev" mount option causes the system to not interpret character or block special devices. Executing character or block special devices from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access. 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
Red Hat Enterprise Linux 8 Security Technical Implementation Guide	2022-09-07

Details

Check Text ( C-33179r568276_chk )
Verify "/dev/shm" is mounted with the "noexec" option: $ sudo mount \| grep /dev/shm tmpfs on /dev/shm type tmpfs (rw,nodev,nosuid,noexec,seclabel) Verify that the "noexec" options is configured for /dev/shm: $ sudo cat /etc/fstab \| grep /dev/shm tmpfs /dev/shm tmpfs defaults,nodev,nosuid,noexec 0 0 If results are returned and the "noexec" option is missing, or if /dev/shm is mounted without the "noexec" option, this is a finding.

Check Text ( C-33179r568276_chk )

Verify "/dev/shm" is mounted with the "noexec" option:

$ sudo mount | grep /dev/shm

tmpfs on /dev/shm type tmpfs (rw,nodev,nosuid,noexec,seclabel)

Verify that the "noexec" options is configured for /dev/shm:

$ sudo cat /etc/fstab | grep /dev/shm

tmpfs /dev/shm tmpfs defaults,nodev,nosuid,noexec 0 0

If results are returned and the "noexec" option is missing, or if /dev/shm is mounted without the "noexec" option, this is a finding.

Fix Text (F-33154r568277_fix)
Configure the system so that /dev/shm is mounted with the "noexec" option by adding /modifying the /etc/fstab with the following line: tmpfs /dev/shm tmpfs defaults,nodev,nosuid,noexec 0 0