The Red Hat Enterprise Linux operating system must prevent files with the setuid and setgid bit set from being executed on file systems that are being imported via Network File System (NFS).

STIG ID: RHEL-07-021020  |  SRG: SRG-OS-000480-GPOS-00227 | Severity: medium |  CCI: CCI-000366

Vulnerability Discussion

The "nosuid" mount option causes the system to not 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 unprivileged users to attain unauthorized administrative access.

Check

Verify file systems that are being NFS imported are configured with the "nosuid" option.

Find the file system(s) that contain the directories being exported with the following command:

# more /etc/fstab | grep nfs

UUID=e06097bb-cfcd-437b-9e4d-a691f5662a7d /store nfs rw,nosuid 0 0

If a file system found in "/etc/fstab" refers to NFS and it does not have the "nosuid" option set, this is a finding.

Verify the NFS is mounted with the "nosuid" option:

# mount | grep nfs | grep nosuid
If no results are returned, this is a finding.

Fix

Configure the "/etc/fstab" to use the "nosuid" option on file systems that are being imported via NFS.
This website is not created by, run, approved, or endorsed by the U.S. Department of Defense. Use at your own risk. This website is created by open-source software.