Firephorm - the anti-phorm Firefox extension

Martin Brinkmann
Oct 14, 2008
Updated • Sep 19, 2013

We have covered Phorm before here on Ghacks. It is a very scary cooperation between several Internet Service Providers and advertising companies. The Internet Service Providers install tracking cookies on user systems and create unique profiles for each user which is then used by cooperating advertising agencies to display targeted advertisement to the user.

Especially British Internet Service Providers seem inclined to make use of Phorm to earn an extra pound. The best way of dealing with such companies would be change to another phorm-free provider as soon as possible. This however is not always possible. That's when anti-phorm tools come into play. They are also great for the time it takes to transfer the account from one provider to another.

Why is Phorm so dangerous? The tracking is definitely a privacy issue. You cannot opt out of the tracking and data like search queries, and visited websites are stored and analyzed. Since British companies are world renowned for data safety it is only a matter of time before data leaks user profiles.

Firephorm is a Firefox extension that is forging the cookies placed on the system to make the tracking system useless. It provides the option to forge the master cookie and the tracking cookies to either poison the system by using random cookies, using an opt-out cookie or from an UID list specified by the user.

The Firefox extension modifies http requests and response headers and can also warn the user if a webpage request was redirected via Phorm's

Update: The Firefox extension is no longer available. It is likely that this is a reaction to Phorm not really making progress in the UK or Europe in regards to ISPs that have implemented the service.

According to Wikipedia, there are only a handful of ISPs that have partnered with Phorm openly: Telefonica in Brazil, TTNET-Türk in Turkey and Romtelecom in Romania.


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  1. Matt said on October 14, 2008 at 8:59 pm

    Another solution for this type of issue:
    Firefox + Noscript + CS Lite + Adblock Plus + OpenDNS.

  2. USBman said on October 14, 2008 at 7:45 pm

    OK, I’m interested… expect there is no actual link to the extension on the Firephorm page!!!

    Any help?

  3. Sam Keen said on October 14, 2008 at 7:24 pm

    This is pretty sweet.

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