Mellisa the CAPTCHA stripper.

Trend Micro beleive that spammers have created a revealing Windows game which shows a woman in various states of undress when people correctly identify the text shown in an accompanying CAPTCHA image.

CAPTCHA, short for Completely Automated Public Turing test to tell Computers and Humans Apart, was started when bots started spreading over the Internet a few years ago. The CAPTCHA system was aimed at preventing automated submissions/registrations of bots by prompting the user to validate himself as a human, usually requiring the user to input a sequence of alphanumeric characters contained in an image supposedly “unreadable” by a machine.

If you correctly input the letters, and press “go”, “Melissa” the stripper reveals more of herself and another CAPTCHA picture for you to identify.

The “answers” however are sent to a remote server, where someone eagerly awaits them to circumvent a Captcha system to gain e-mail accounts or membership to forums to post spam links.

So the strip-tease game is actually a ploy by ingenious malware authors to identify and match ambiguous CAPTCHA images from legitimate sites, using the unsuspecting user as the decoder of the CAPTCHA image.

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