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).

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-72045	RHEL-07-021020	SV-86669r2_rule		Medium

Description
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.

STIG	Date
Red Hat Enterprise Linux 7 Security Technical Implementation Guide	2018-11-28

Details

Check Text ( C-72277r2_chk )
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.

Check Text ( C-72277r2_chk )

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 Text (F-78397r2_fix)
Configure the "/etc/fstab" to use the "nosuid" option on file systems that are being imported via NFS.