Here's a sneaky one for you. According to Sophos, a piece of spyware is masquerading as a Flash player plug-in for Firefox. Its installation screen looks legit (per examples in the Sophos post), and it will even show up thereafter in the list of Firefox extensions as "Adobe Flash Player 0.2."
But you don't get video with this plugin -- instead, it will spy on your Google searches and send the data to a "remote server," and will also insert ads onto Web pages you view.

















