1.1.4 Ensure nosuid option set on /tmp partition (Scored)

Level 1 - Server 
Level 1 - Workstation

The nosuid mount option specifies that the filesystem cannot contain setuid files.

Since the /tmp filesystem is only intended for temporary file storage, set this option to ensure that users cannot create setuid files in /tmp.

If a /tmp partition exists run the following command and verify that the nosuid option is set on /tmp:

# mount | grep /tmp 
tmpfs on /tmp type tmpfs (rw,nosuid,nodev,noexec,relatime)

Edit /etc/systemd/system/local-fs.target.wants/tmp.mount to add nosuid to the /tmp mount options:

[Mount] 
Options=mode=1777,strictatime,noexec,nodev,nosuid

Run the following command to remount /tmp:

# mount -o remount,nosuid /tmp

systemd includes the tmp.mount service which should be used instead of configuring /etc/fstab. Mounting options are configured in the Options setting in /etc/systemd/system/tmp.mount.