Masking Agent

Masking Agent is a Firefox add-on that hides your platform detais.

About

Your web browser reveals more information than you think. Notably, with each web access the browser reveals the Operating System (e.g. Windows 8.1, Mac OS X 10.9, or Ubuntu 14.04) and the CPU. Check the Masking Agent demo for your configuration. Mostly, the information about your platform is not needed to browse the web, at all. If you're using an older, more vulnerable computer, you may not want to be so generous with this information. In general, it's a good idea to control the information that you transmit.

There are several Firefox add-ons available that let you mimic a completely different browser, i.e. browser application and platform. But none of them meet my requirements:

So, I made Masking Agent.

Demo

The information shown below is available to every web site. If you don't have Masking Agent installed and enabled, your platform details are plainly visible. Revisit this page with Masking Agent installed to see the differences.

JavaScript appVersion browser compatibility (requires JavaScript)
JavaScript OS/CPU platform details (requires JavaScript)
JavaScript Platform platform summary (requires JavaScript)
JavaScript User-Agent browser signature (requires JavaScript)
HTTP User-Agent browser signature CCBot/2.0 (http://commoncrawl.org/faq/)

Download

Masking Agent is hosted at a Mozilla add-on page: https://addons.mozilla.org/en-US/firefox/addon/masking-agent/.

You can download it directly: https://addons.mozilla.org/firefox/downloads/latest/371677/addon-371677-latest.xpi.

Frequently Asked Questions

Known Issues

Resetting Masking Agent

When the add-on is not working as described:

  1. In Firefox, go to your installed add-ons and find Masking Agent.
  2. Click the "Disable" button of this add-on.
  3. Open a new tab or window, and navigate to address about:config?filter=general.*.override
  4. From the displayed list of preferences, reset the following preferences, i.e. right-click each preference separately, and select "Reset" from the context menu:
    • general.appversion.override
    • general.oscpu.override
    • general.platform.override
    • general.useragent.override
  5. Return to your installed add-ons and re-enable Masking Agent.

Feedback

Please add your review at https://addons.mozilla.org/en-US/firefox/addon/masking-agent/reviews/add.