Profile Applicability:
 • Level 1

Description:
 The nodev mount option prevents device files from being interpreted on the mounted filesystem. Applying this option to /var/log restricts the creation and use of device files in the log directory, reducing security risks.

Rationale:
 Setting the nodev option on /var/log helps prevent attackers from creating device files that can be exploited for privilege escalation or unauthorized access.

Impact:
 Pros:

  • Prevents device file exploitation on /var/log.

  • Improves overall system security posture.

Cons:

  • May affect rare legitimate uses of device files in /var/log.

Default Value:
 By default, nodev is usually not set on /var/log unless explicitly configured.

Pre-requisites:

  • Root or sudo privileges to modify /etc/fstab and remount filesystems.

  • /var/log must be mounted as a separate partition.

Remediation:

Test Plan:

Using Linux command line:

  1. Check current mount options for /var/log:

     mount | grep /var/log

  2. Verify if nodev is included in /etc/fstab for /var/log:

     grep /var/log /etc/fstab


    Expected output: Mount options for /var/log include nodev.

Implementation Plan:

Using Linux command line:

  1. Edit /etc/fstab to add nodev to /var/log mount options. Example:
    /dev/<partition>  /var/log  ext4  defaults,nodev,nosuid,noexec  0  0

  2. Remount /var/log with new options without reboot:

     mount -o remount,nodev /var/log

  3. Verify mount options:

     mount | grep /var/log

Backout Plan:

Using Linux command line:

  1. Remove nodev from /var/log mount options in /etc/fstab.

  2. Remount /var/log without nodev:

     mount -o remount /var/log

  3. Verify mount options:

     mount | grep /var/log

References: