Melissa AKA TROJ_CAPTCHAR.A
At first glance you may be forgiven for thinking that Melissa is nothing more than a naughty little tease.
In reality, she’s just plain naughty.
TROJ_CAPTCHAR.A comes disguised as a small strip-tease game featuring ‘Melissa’ who begins by wearing very little and promising to slowly remove what’s left.
Aimed at young pubescent boys pretty well any hot blooded male, Melissa makes you work in return for peeling her clothes off – users must identify and enter the letters on the attached CAPTCHA.
On the face of it, this may seem quite harmless but, in reality, the answers to the CAPTCHAs are being sent to a remote server where a malicious user patiently awaits them.
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 said image.
The reason for this is unknown, though it could well be for spamming purposes.
If so, it certainly signifies an interesting (and eye-catching) new method of circumventing anti-spamming measures.