Details

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

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

Run the following command to remount /tmp :

# mount -o remount,nodev /tmp

Notes:

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/local-fs.target.wants/tmp.mount.

Supportive Information

The following resource is also helpful.

• https://workbench.cisecurity.org/files/2619

This security hardening control applies to the following category of controls within NIST 800-53: Configuration Management.This control applies to the following type of system Unix.

References

• 800-53|CM-6
• CSCv7|5.1

Source

• Tenable.com/audits