Hackers have broken into an antivirus company, stolen its customer list and emailed them all with a worm disguised as a company newsletter.
Moscow-based Kaspersky Labs is investigating how the hackers managed to break into its computer system and steal the mailing list for its Virus News update.
A copy of the Virus News email, infected with the Braid worm, was sent out to subscribers.
Eugene Kaspersky, founder and head of research for Kaspersky Labs, said in an advisory that the company would make sure this type of attack would never succeed again.
The company has not heard of any infections resulting from the fake email, Kaspersky said, but it has offered free technical services to anyone who is hit as a result.
The Braid worm, which is a variant of the Lovebug virus, is written in Visual Basic and has its own email software, which means that it can spread itself even if a victim's computer does not have an email facility.
The virus infects computers running on Windows. It makes several copies of itself on the hard drive, searches for email addresses and then sends itself out to them.
The worm has not spread very widely but is rated as number five on MessageLabs' daily top ten.
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