It goes under a variety of names - W32Blackmail (Symantec), Nyxem.e (F-Secure), [email protected] (McAfee) and more lurid nicknames including Kama Sutra and Blackworm - which might explain why the latest worm infection appears to be spreading rapidly.
Unprotected users are warned that they could lose many of their data files and may be forced to rebuild their systems if infected.
First identified by Sophos on 16 January, the infection arrives in an attachment carried by an email message claiming to offer the viewer a look at "Kama Sutra pics".
If the virus is activated by opening the attachment, it will run a script that deletes common file formats and alters the registry entries of security-related applications from suppliers including Symantec/Norton, McAfee, Trend Micro and Kaspersky.
The worm in...