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/2925

Item Details

Category: CONFIGURATION MANAGEMENT, SYSTEM AND COMMUNICATIONS PROTECTION

References: 800-53|CM-6, 800-53|SC-7(10), CSCv7|5.1, CSCv7|13

Plugin: Unix

Control ID: 195742a798be32c599bde828d9416ae0c5685c9f6320d6762a41846066cc86b1