Archive for June, 2009

Firefox undermined by Redmond sneak-ware

Posted in Uncategorized on June 6, 2009 by Si

As reported in various places, including El Reg (, the .NET Framework 3.5 Service Pack 1 update installed a Firefox extension without asking the user’s permission. The ClickOnce extension gives websites the ability to easily install software on the client, a major security hole and one that many users chose Firefox for to avoid. The extension is installed for all Firefox users so can’t be uninstalled through the GUI (maybe that needs to be addressed in a future release of FF!).

Anyway, the solution for those eager to remove this sneak-ware from is available from (, but the steps are reiterated below:

  1. Open Registry Editor (type regedit in the Start menu Search box in Vista/Windows 7, or in XP’s Run window).
  2. Expand the branches to the following key:
    • On 32-bit systems: HKEY_LOCAL_MACHINE \ SOFTWARE \ Mozilla \ Firefox \ Extensions
    • On x64 systems: HKEY_LOCAL_MACHINE \ SOFTWARE \ Wow6432Node \ Mozilla \ Firefox \ Extensions
  3. Delete the value named {20a82645-c095-46ed-80e3-08825760534b} from the right pane.
  4. Close the Registry Editor when you’re done.
  5. Open a new Firefox window, and in the address bar, type about:config and press Enter.
  6. Type microsoftdotnet in the Filter field to quickly find the general.useragent.extra.microsoftdotnet setting.
  7. Right-click general.useragent.extra.microsoftdotnet and select Reset.
  8. Restart Firefox.
  9. Open Windows Explorer, and navigate to %SYSTEMDRIVE%\Windows\Microsoft.NET\Framework\v3.5\Windows Presentation Foundation.
  10. Delete the DotNetAssistantExtension folder entirely.
  11. Open the Add-ons window in Firefox to confirm that the Microsoft .NET Framework Assistant extension has been removed.