Over 10,000 remote-access computers in the Nordic countries are sending out the infected message and, according to the antivirus company F-Secure, the virus is spreading quickly in Sweden.
The FBI warned internet users on Tuesday not to open the attachment to the email, which contains subject headers including “Your IP was logged” and “You_visit_illegal_websites”.
Recipients are instructed to answer the questions in the attached document, but opening the attachment activates the virus. It then spreads via the email addresses stored in the infected computer.
The virus, which is also being spread in emails purporting to come from the CIA, is a variant of the mass-mail Sober ‘worm’.