1.1.5 Ensure nosuid option set on /tmp partition

Information

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

Rationale:

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

Solution

IF /etc/fstab is used to mount /tmp
Edit the /etc/fstab file and add nosuid to the fourth field (mounting options) for the /tmp partition. See the fstab(5) manual page for more information.
Run the following command to remount /tmp :

# mount -o remount,nosuid /tmp

OR if systemd is used to mount /tmp:
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 restart the systemd daemon:

# systemctl daemon-reload

Run the following command to restart tmp.mount:

# systemctl restart tmp.mount

See Also

https://workbench.cisecurity.org/files/3636

Item Details

Category: ACCESS CONTROL, CONFIGURATION MANAGEMENT, MEDIA PROTECTION, SYSTEM AND SERVICES ACQUISITION

References: 800-53|AC-3, 800-53|AC-5, 800-53|AC-6, 800-53|CM-2, 800-53|CM-6, 800-53|CM-7, 800-53|CM-7(1), 800-53|CM-9, 800-53|MP-2, 800-53|SA-3, 800-53|SA-8, 800-53|SA-10, CSCv7|5.1

Plugin: Unix

Control ID: 379d558d47f1e8a5da660f458383a277f22a5d8ee69f8fff8edf5d3676981131