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Hardening Firefox

Firefox is the most private browser out of the box, but we can make it better. Much better.

Hardening involves modifying the user.js file in your Firefox profile to override default settings. This disables telemetry, pocket, sponsored shortcuts, and strengthens fingerprinting resistance.

If you don’t want to configure anything, download LibreWolf. It is a fork of Firefox with all of the below applied by default.

Arkenfox is the community standard for a privacy-focused user.js template.

  1. Download Firefox: Install the standard release.
  2. Locate Profile: Go to about:support in the URL bar. Look for “Profile Folder” and click “Open Directory”.
  3. Create user.js:
    • Go to the Arkenfox GitHub.
    • Download the user.js file.
    • Place it inside your Profile Folder.
  4. Restart Firefox: The settings will be applied automatically on search.

Hardening is incomplete without extensions.

  1. uBlock Origin: The only adblocker you need.
    • Tip: Go to Settings > Filter lists > Enable everything under “Ads”, “Privacy”, “Malware domains”, and “Annoyances”.
  2. Skip Redirect: Skips intermediary tracking pages.
  3. CanvasBlocker: (Optional if using Arkenfox, as it has built-in resistance) Fakes canvas API readout preventing fingerprinting.

If you just want to toggle a few things without a full user.js:

  • privacy.resistFingerprinting = true (Warning: breaks some site layouts/timezones)
  • network.dns.disablePrefetch = true
  • network.prefetch-next = false