A tactic frequently used by criminals involves convincing users that a virus has infected their computer, then suggesting that they download (and pay for) fake antivirus software to remove it.^[1] Usually the virus is entirely fictional and the software is non-functional or malware itself.^[2] According to the Anti-Phishing Working Group, the number of scareware packages in circulation rose from 2,850 to 9,287 in the second half of 2008.^[3] In the first half of 2009, the APWG identified a 585% increase in scareware programs.^[4]

The "scareware" label can also apply to any application or virus (not necessarily sold as above) which pranks users with intent to cause anxiety or panic.