cyberstrikeus Ensure noexec option set on /tmp partition
Description
The noexec mount option specifies that the filesystem cannot contain executable binaries.
Rationale
Since the /tmp filesystem is only intended for temporary file storage, set this option to ensure that users cannot run executable binaries from /tmp.
Impact
None noted.
Audit Procedure
Command Line
# If a /tmp partition exists, verify that the noexec option is set.
# Run the following command and verify that nothing is returned:
findmnt -n /tmp | grep -v noexec
Expected Result
No output should be returned.
Remediation
Command Line
# Edit the /etc/fstab file and add noexec 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,noexec /tmp
# OR Edit /etc/systemd/system/local-fs.target.wants/tmp.mount to add noexec to the /tmp mount options:
# [Mount]
# Options=mode=1777,strictatime,noexec,nodev,nosuid
# Run the following command to remount /tmp:
mount -o remount,noexec /tmp
Default Value
Not set by default.
References
- CIS Controls Version 7 - 2.6 Address unapproved software: Ensure that unauthorized software is either removed or the inventory is updated in a timely manner.
Profile
Level 1 - Server / Level 1 - Workstation, Assessment: Automated