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
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.