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V-269311

CAT II (Medium)

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

Rule ID

SV-269311r1261560_rule

STIG

Cloud Linux AlmaLinux OS 9 Security Technical Implementation Guide

Version

V1R8

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.

Check Content

Note: For systems that use BIOS and for vfat systems, this requirement 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,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.

Fix Text

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