Sober still on the loose

A new Sober variant is the most frequently detected virus worldwide, according to security companies.

Sober.AH arrives as an attachment to an email that pretends to be from the FBI, advising users that they have accessed illegal internet addresses.

As with its predecessors, the mass mailing worm can send itself in email in either English or German depending on the recipient's address.

When users run the file containing Sober.AH, a window is displayed with a false error message and the worm sends itself to all email addresses it finds.

Luis Corrons, director of PandaLabs, said: "The propagation capacity of Sober.AH means that every time there is a new infection, the chances of receiving an infected email increase exponentially. For this reason users should treat email received with caution. Nevertheless, it is advisable to scan all mail with an up-to-date antivirus."