London, Dec 16 (ANI): Experts are warning internet users against Koobface computer virus targeting popular social networking sites in the run up to Christmas.
It is said that Facebook users are most at risk from a variant of the Koobface virus, which comes in disguise as a Festive greetings video, hosted on a YouTube site.
The new virus is "particularly nasty" and encourages victims to participate manually in creating a new Facebook account to help spread the worm.
The attacks work by posting malevolent links on Facebook pages.
It invites users to click on the Christmas card videos, which takes control of the PC to the attackers.
Internet security company Panda Security has been tracking the latest variant of the Koobface worm from its labs in Spain.
"There is no doubting that this latest Koobface attack represents a serious threat to social networkers," Sky News quoted company's UK managing director Peter Lautin as saying.
"If someone runs the infected file on their Facebook or MySpace page, the worm will automatically log in to their account and several other social networking sites, sending malicious messages to all their friends.
"The more people who use an application such as Facebook, or any other means of social networking, the more likely they are to be targeted by bad guys to send out malicious threats such as Koobface," Lautin added.
The victim sees a warning message, asking them to solve a Captcha (Completely Automated Public Turing Test To Tell Computers And Humans Apart) puzzle within three minutes.
A timer ticks down and if the puzzle goes unsolved after the allotted time, the PC freezes up.
According to the experts, rebooting the computer will not help and the only way to end the loop is to solve the Captcha puzzle.
The victim would then be able to use their PC as normal, however, the attacker would still have control. (ANI)