News 

The worm sends an instant chat message to other Skype users in the person's contacts, which contains a JPEG image. The image actually links to a virus file, which will ask for permission to save or run a .scr file on the user's PC. Users who do this will find their PC is infected.

"The chat message, of which there are several versions, is cleverly written and may appear to be a legitimate chat message, which may fool some users into clicking on the link," Skype claims on its blog.

Skype claims the leading anti-virus vendors have already updated their products to combat this worm. It also provides a guide to removing the virus via the Registry on its blog.

It's the second time in recent weeks that Skype has suffered from a serious technical flaw. In August, the company blamed the cumulative effect of people restarting their systems after a Windows Update for a 48-hour outage on the telephone service.