How to remove Microsoft .NET Framework Assistant (Vulnerability) from Firefox

By | June 4, 2009

How to remove Microsoft .NET Framework Assistant (Vulnerability) from FirefoxMicrosoft has secretly added an add-on to Firefox which you can not remove and which adds the same security problems of Internet Explorer (allowing third parties to install software without your permission) to Firefox.

Microsoft may be Firefox’s worst vulnerability: http://blogs.techrepublic.com.com/security/?p=1716&tag=nl.e019

In a surprise move this year, Microsoft has decided to quietly install what amounts to a massive security vulnerability in Firefox without informing the user. Find out what Microsoft has to say about it…”

Here is how to undo this dastardly deed:

If you take a look at the installed add-ons in Firefox you might notice an add-on called Microsoft .net Framework Assistant. That add-on is different from most other installed add-ons. The first thing that you will notice is that you cannot uninstall it as the uninstall option is inactive in Firefox. You might also realize that you did not install that add-on actively which means it must have been installed by another application.

The Firefox Extension Guru posted a walkthrough on how to remove the Microsoft .Net Framework Assistant. It basically comes down to the following steps (it might be a good idea to backup all data before proceeding).

  • Make sure Firefox is closed.
  • Go to C:WINDOWSMicrosoft.NETFrameworkv3.5Windows Presentation FoundationDotNetAssistantExtension in Windows Explorer and delete everything in that folder but keep the folder name.
  • Start Firefox. The add-on should not be in the list anymore.

(I have FF 3.0.10 and started this with .NET disabled. At this step the add-on was still in the list … but I followed the steps below too, then Enabled the .Net add-on, restarted FF, it WAS gone. And better yet, Firefox started much faster with this stealth Microsoft hack removed.)

  • Type about:config in the Firefox address bar.
  • Filter for the entry general.useragent.extra.microsoftdotnet
  • Right-click that entry and select Reset

The process is apparently a bit more complicated for Firefox 3.1 beta versions as the Microsoft .Net Framework Assistant is not yet compatible with that version of Firefox and thus not completely installed.

2 thoughts on “How to remove Microsoft .NET Framework Assistant (Vulnerability) from Firefox

  1. Noelene

    I got the same message Simone.I am not that great with computers,but I clicked on tools then add ons.There was an option to uninstall,so I did and it worked,hopefully it will stay gone.my son installed windows 7 on my computer,I don’t like it,too hard to find anything.

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