Macintosh users bugged by Sobig-F worm, Sophos Anti-Virus explains how Windows worm can be a nuisance

August 21, 2003 Sophos Press Release

An Apple iMac computer

Sophos technical support has received a number of calls from Apple Macintosh users concerned about the fast-spreading W32/Sobig-F worm.

Although Macintosh computers cannot be infected by the Sobig-F worm, which is Windows-specific, users can still receive large numbers of the emails generated by the worm in their inbox. One unfortunate home user has reported receiving over 6000 instances of the Sobig-F worm in their private email account. All such emails have to be deleted if they are not blocked at the email gateway.

Furthermore, some Macintosh users have received numerous warnings that their computers are infected by W32/Sobig-F because they have received emails from poorly set-up auto-responders at email gateways. These warnings are nonsense, and the consequence of a computer automatically replying to an infected email (not realising that W32/Sobig-F forges the 'sender' information), but that has not stopped some Macintosh users from worrying that they may have been infected after all.

"Macintosh owners can safely delete any emails they receive warning they are infected and copies of the worm which are sent to them," said Graham Cluley, senior technology consultant for Sophos Anti-Virus. "Even though Macintoshes are immune from infection from W32/Sobig-F they may still experience email slowdown simply because of the vast number of emails flying around the internet, clogging up the email systems of companies."

Sophos has published more information on how auto-responders have contributed to the problem, rather than eased the current difficulties with email worldwide.