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V-257856

CAT II (Medium)

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).

Rule ID

SV-257856r1044938_rule

STIG

Red Hat Enterprise Linux 9 Security Technical Implementation Guide

Version

V2R8

CCIs

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 Content

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 Text

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