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

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.
Example: vim /etc/fstab
Add the following line:
tmpfs /tmp tmpfs defaults,rw,nosuid,nodev,noexec,relatime 0 0
Run the following command to remount /tmp :

# mount -o remount,nosuid /tmp

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

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

Run the following command to remount /tmp :

# mount -o remount,nosuid /tmp

See Also

https://workbench.cisecurity.org/files/2688

Item Details

Category: CONFIGURATION MANAGEMENT

References: 800-53|CM-6, CSCv7|5.1

Plugin: Unix

Control ID: ffc6d57238b6d2d8a69362f88c9f746f312f79c8c1fdc716f2fddd74b309a0fe