“This makes Sobig.F the fastest growing virus ever, surpassing the infamous LoveBug, Klez and Kournikova viruses. All initial copies originated from the United States, where the virus is currently most prevalent. As Sobig.F continues its rapid spread today businesses are also advised to be on high-level alert. Sobig.F, first detected on 18th August, is the sixth variant issued in the Sobig virus series and appears to be the most sophisticated to date. Since the first Sobig virus was issued on January 9th 2003, MessageLabs has intercepted almost three million copies of Sobig variants.

‘Yesterday marked an unprecedented new level in virus propagation and demonstrated the growing ability of virus writers to disrupt business around the globe,’ said Mark Sunner, Chief Technology Officer at MessageLabs. ‘The Sobig virus writer’s use of an inbuilt expiry date indicates that he is committed to inventing new and improved versions. Each variant released so far has exceeded the previous one in growth and impact during the critical initial window of vulnerability.”

Sobig is a mass-emailing virus that can spoof the sender’s address, fooling the user into believing the email is from a legitimate source and then opening the email. The email often contains the following header: “Subject: Re:details” and the text “Please see the attached file for details”. The attachment names may include: your_document.pif, details.pif, your_details.pif, thank_you.pif, movie0045.pifm, document_Fall.pif, application.pif, docment_9446.pif.

Once the virus has infected your machine it attempts to connect to a website to download a backdoor Trojan, leaving your computer vulnerable to security breaches by hackers or other viruses. The current Sobig virus to email ratio is approximately 1 in 17 and the virus is spreading at such a rate it is expected to continue to stay at high-level status for the next few weeks. However, like past Sobig viruses, the Sobig.F virus has an expiry date and is set to deactivate on September 10th, which will effectively stop this variant from spreading further after that date. ” MessageLabs

I was aware of the news that the virus had an inborn expiration date and wondered about the significance of that. Now I know it has ominous implications. By now, I’m sure you have received emails with the virus. Symantec has a downloadable removal tool which scans your hard drive for traces of Sobig.F and expunges them.