Miscreants have created a worm that uses the chat function built into Skype to spread.
The malware - variously known as either Ramex, Skipi or Pykspa - sends a short message containing a link to a seemingly benign jpeg file to contacts of users with infected Windows PCs. Users who click on the link are prompted to download and run a copy of an image (actually a malware payload), after which their machines would become infected.
Ramex contains functions designed to disable anti-malware packages on infected PCs, as well as altering the hosts file to disable the downloading of security updates. It then uses the Skype API to send the messages in either Lithuanian and English, depending on the client's user interface. Typical examples of the message it sends include "really funny", "look what crazy photo Tiffany sent to me, looks cool" and "what ur friend name wich is in photo?"
Anti-virus firm F-Secure reports the detection of two variants of the malware thus far. Both display soap bubbles (one of the default built-in wallpapers in Windows) on infected PCs.
Anti-virus vendors are in the process of updating detection to seek out the malware. Meanwhile, Skype users are urged to be wary of clicking on even seemingly benign links.
It's unclear how many victims Ramex has claimed but entries on Skype-related forums posted on Monday provide evidence that it's causing a fair amount of trouble. Skype's heartbeat blog contains an entry on the worm that contains manual removal instructions.
Skype's instant messaging client is periodically misused as a vector to spread malware, and Ramex is far from unique. For example, back in April a Skype instant messaging worm posed as a picture of a scantily clad young woman wearing stilettos.
The twist in the latest attack comes in the plausibility of the social engineering tricks it uses in an attempt to fool users into getting infected.
Last year net security firm Sophos conducted a poll of system administrators and found that 86.1 per cent of those who expressed an opinion wanted the power to control use of VoIP in their companies, with 62.8 per cent saying blocking was essential. As well as the risk of Skype acting as a vector for malware, sys admins are also concerned about the risk of chat component as a conduit for data leakage from corporates. ®