Linux - System Preferences - Ensure Mounting of Freevxfs Filesystems is Disabled

What the freevxfs filesystem disabler does

This Automox Worklet™ detects whether the freevxfs kernel module is loaded on your Linux endpoint and, if found, disables it. The Worklet creates a kernel module configuration file that prevents freevxfs from loading on future boots and unloads any currently loaded module.

The freevxfs filesystem is an obscure, rarely-used format that is not needed on most modern Linux systems. Removing unused filesystem drivers reduces the kernel's attack surface and eliminates potential security vulnerabilities from code paths that are unlikely to be actively maintained.

d/freevxfs.conf".

Why disable freevxfs mounting on your endpoints

Unused kernel modules create unnecessary attack surface by introducing additional code paths that could contain exploitable vulnerabilities. The freevxfs filesystem is rarely used in modern Linux deployments, yet when left enabled, it consumes system resources and increases the complexity of your kernel.

The CIS Distribution Independent Linux Benchmark explicitly recommends disabling mounting of unused filesystem types to minimize security risks. By removing the freevxfs module, you reduce the kernel's attack surface and eliminate potential exploitation vectors.

Applying this Worklet across your Linux fleet maintains consistent security posture and demonstrates compliance with industry security standards.

How freevxfs module removal works

1. Evaluation phase: The Worklet checks if the freevxfs filesystem is available on the system using modprobe -n -v freevxfs. If available, it then uses lsmod to determine whether the freevxfs module is currently loaded in the kernel.

2. Remediation phase: The Worklet creates a configuration file at /etc/modprobe.d/freevxfs.conf with the line install freevxfs /bin/true, which prevents the module from loading. It then unloads any currently loaded freevxfs module using rmmod freevxfs.

Freevxfs remediation requirements

• Linux operating system (all distributions supported)

• Root or sudo access required for kernel module operations

• freevxfs filesystem support must be compiled into the kernel or available as a loadable module

• No active mounts using the freevxfs filesystem

Expected freevxfs filesystem state

After remediation, the freevxfs kernel module will no longer load on your endpoints. You can expect these specific outcomes:

• The configuration file /etc/modprobe.d/freevxfs.conf exists with the line "install freevxfs /bin/true"

• Running lsmod no longer shows the freevxfs module in the loaded kernel modules list

• The module block persists across reboots through the modprobe configuration

• Attempting to mount freevxfs filesystems will fail with an error

How to validate verify mounting of freevxfs filesystems is disabled changes

1. Run this Worklet on a pilot Linux endpoint and review evaluation output for verify mounting of freevxfs filesystems is disabled.

2. Confirm Automox activity logs show successful completion and exit code 0.

3. Verify endpoint state using checks aligned to evaluation script logic, such as else, exit.

4. Validate remediation effects from script operations such as function, touch, rmmod, then rerun evaluation for compliance.

For technical validation, compare endpoint state to the Worklet evaluation logic and remediation flow for verify mounting of freevxfs filesystems is disabled. This supports repeatable system preferences workflows, faster change control review, and auditable compliance evidence.

Useful script references for this Worklet include evaluation operations such as else, exit and remediation operations such as function, touch, rmmod. Use these indicators to verify that endpoint changes match intended policy outcomes.