According to PandaLabs, which has researched the reworked Koobface, Christmas is one of hackers' favourite seasons. Every year a new IT security threat manages to trick numerous people, exploiting the festive season as bait.
With Koobface.GK, PandaLabs said that the malware's bait consists of a Christmas greetings video hosted on a YouTube page. After playing the video, or clicking a link on the page, users will download and install Koobface.
PandaLabs said that, when Koobface is installed on a computer, a captcha (completely automated public turing test) image appears and, if victims fail to enter the corresponding response, the worm threatens to reboot the PC within three minutes.
But, when the three minutes are up, nothing happens, although the PC is frozen.
On top of this, PandaLabs said that, every time the captcha text is entered, Koobface registers a new domain where the video will be hosted in order to continue being distributed.
According to Luis Corrons, technical director of PandaLabs, social networks have become one of the methods most frequently used by hackers to spread their malware and infected creations, owing to the false sense of security many users have regarding content published on these services.
"Users generally trust the messages and content they receive, and consequently hackers get a high level of response through these channels", he explained.
Corrons noted that many send Christmas greetings to their family and friends over the web.
"Infection figures are always high at this time of the year, as new viruses emerge that take advantage of this increased user activity and every Christmas we see new malware designed specifically for the festive season", he said.