Facebook users unwittingly spread Koobface worm
Facebook users are being targeted by a nasty new version of the Koobface worm -- dubbed Koobface.GK -- that compels its victims to manually participate in creating a new Facebook account to help spread the worm.
The attackers are posting malicious links on Facebook wall pages enticing folks to click on a cutesy Christmas video. Attempts to play the video turns over control of the PC to the attacker, says PandaLabs researcher Sean-Paul Correll. The victim next sees a Windows warning message requiring them to solve a CAPTCHA puzzle within three minutes.
A timer ticks down. If the puzzle goes unsolved after three minutes, the PC freezes up. Rebooting won't help. The CAPTCHA puzzle will reappear. The only way to end the loop is to solve the CAPTCHA. The victim can then use his or her machine as normal. But the attacker still has control.
