Stiletto Worm Spread Via Skype IM

Playing on the sex factor like a lot of worms do, the Mal/Pykse-A worm is spreading via Skype’s IM chat system.

The worm poses as a link to a photograph of a young woman. Clicking on the link does display an image of a scantily clad model wearing stiletto heeled shoes, but only after infecting the PC with a downloader Trojan which then installs the worm.

“Once it’s up and running, the Pykse worm attempts to connect to a number of remote websites, presumably in an attempt to generate advertising revenue for them by increasing their number of ‘hits’,” said Graham Cluley, senior technology consultant for Sophos. “It’s another example of the methods that malware authors can use to make money. With an ever increasing wave of malicious attacks, companies need to ensure that not only do they have secure defenses in place, but also that they are enforcing policies about what programs their users can run and which websites their PCs can visit.”

Remote sites connected to by the worm currently contain content referencing “The Living Africa” ripped from a legitimate site: library.thinkquest.org. Some of the sites includes an invisible iframe, which sucks in content from online advertising companies. Others don’t contain advertising content, and seem to contain just mirror of the legit page. However, they could be updated by hackers in future to contain malicious content if they so chose.

Sophos notes that there have been a number of worms which have spread via Skype instant messaging in the past. None of them have been particularly widespread compared to other major outbreaks of malware.