Viruses don't want to be removed, so the nastier ones will fight to stay put by disabling protection software, cloaking their presence and even generating fake windows and dialog boxes to give you a bum steer. Looks like malicious extensions are getting in on the action too, doing whatever they can to evade uninstallation.
As Pieter Arntz of Malwarebytes explains, this new breed of addons are coded to prevent the user from managing their installed extensions:
The extensions, which have been found in both Chrome and Firefox browsers, block users from removing them by either by closing out pages with extensions/add-ons info, or sending users to a different page, such as an apps overview page, where extensions aren’t listed.
That's just great.
Fortunately, you can sidestep their tricks. In Firefox, just fire up Safe Mode (for the browser, not your OS) and all addons are disabled by default, making removal easy. For Chrome, you'll have to fire up a terminal window and run the Chrome executable with the following switch:
Chrome is usually found in
As with any new addon or extension you might install, read the reviews first and make sure you've acquired it from a reputable source, such as Mozilla's official addon site or the Chrome Web Store.
New Chrome and Firefox extensions block their removal to hijack browsers [Malwarebytes, via gHacks]