RHEL 9 must prevent files with the setuid and setgid bit set from being executed on file systems that are imported via Network File System (NFS).

Documentable No

Rule ID SV-257856r1044938_rule

CCI References

CCI-000366

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 Procedure

Note: If no NFS mounts are configured, this requirement is Not Applicable.

Verify RHEL 9 has the "nosuid" option configured for all NFS mounts with the following command:

$ grep nfs /etc/fstab

192.168.22.2:/mnt/export /data nfs4 rw,nosuid,nodev,noexec,sync,soft,sec=krb5:krb5i:krb5p

If the system is mounting file systems via NFS and the "nosuid" option is missing, this is a finding.

Fix Action

Update each NFS mounted file system to use the "nosuid" option on file systems that are being imported via NFS.