The Bugbear-B virus (W32/Bugbear-B) spreads by sending itself in emails, and by copying itself across networks. It is based upon the original Bugbear worm (W32/Bugbear-A) which was the second most commonly reported virus in 2002. However the new version has a new trick up its sleeve - it is polymorphic, meaning it changes its appearance in an attempt to avoid detection.
Sophos believes there is a chance the virus will become even more widespread as computer users in North America wake up and begin to access their email.
"Viruses which spread via email often follow the sun," said Graham Cluley, senior technology consultant for Sophos Anti-Virus. "As the day begins in countries around the world users will open their email and may open dangerous attachments. It is essential that updated anti-virus and other measures are in place to ensure business continuity."
Sophos has updated its anti-virus products to protect businesses against Bugbear-B, but also offers the following tips to computer users:
*Update anti-virus protection in order to detect and prevent Bugbear-B. Consider introducing procedures for rapid updates to prevent infection from these fast spreading worms and viruses.
*Businesses should block all Windows programs at the email gateway. It is rarely necessary to allow users to receive programs via email.
*Ensure computers using Outlook, Explorer or Outlook Express are running the latest updated versions. Bugbear-B exploits vulnerabilities in some versions of Microsoft's software, but patches have been available for two years.
*Follow safe computing practises: technologies such as mail filtering, firewalls and anti-virus are not "fit-and-forget" solutions. Users still need to act responsibly, especially when dealing with unexpected emails containing attachments.
More information on W32/Bugbear-B and how to update Sophos's products to protect against it can be found at:
Reading our newsletter every Monday will keep you up-to-date with security news.
Receive a daily digest of the latest security news.