← Back to Red Hat Enterprise Linux 9 Security Technical Implementation Guide

V-257862

CAT II (Medium)

RHEL 9 must prevent files with the setuid and setgid bit set from being executed on the /boot/efi directory.

Rule ID

SV-257862r1184295_rule

STIG

Red Hat Enterprise Linux 9 Security Technical Implementation Guide

Version

V2R8

CCIs

CCI-001764

Discussion

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. Satisfies: SRG-OS-000368-GPOS-00154, SRG-OS-000480-GPOS-00227

Check Content

Note: For systems that use BIOS, this is not applicable. 

Verify the /boot/efi directory is mounted with the "nosuid" option with the following command:

$ mount | grep '\s/boot/efi\s'

/dev/sda1 on /boot/efi type vfat (rw,nosuid,relatime,fmask=0077,dmask=0077,codepage=437,iocharset=ascii,shortname=winnt,errors=remount-ro)

If the /boot/efi file system does not have the "nosuid" option set, this is a finding.

Note: This control is not applicable to vfat file systems.

Fix Text

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