Fake antivirus software

First a little background. Fake antivirus software has been around for at least seven years, but this category of attack has exploded in popularity among bad guys in recent months. The technique is simple social engineering, and it works by scaring the target into thinking their system has been infected with a virus (or a whole bunch of them) and then offering to fix the problem—for a fee. The fake AV software often downloads additional Trojans and can actually cause the sort of problems it claims to be solving.
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