1.1.5 Ensure nosuid option set on /tmp partition

Information

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

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 an explicit systemd target 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/benchmarks/8498

Item Details

Category: ACCESS CONTROL, MEDIA PROTECTION

References: 800-53|AC-3, 800-53|AC-5, 800-53|AC-6, 800-53|MP-2, CSCv7|5.1

Plugin: Unix

Control ID: 8e2af9ae2cfe13e75a6e12c3dce436f55cfa7471a94eae25f6c1f9f73112cc35