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

STIG ID: RHEL-09-231100  |  SRG: SRG-OS-000368-GPOS-00154 |  Severity: medium |  CCI: CCI-000366,CCI-001764 |  Vulnerability Id: V-257861

Vulnerability 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

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

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

/dev/sda1 on /boot type xfs (rw,nosuid,relatime,seclabe,attr2,inode64,noquota)

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

Fix

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