A year to the day after the virulent Sobig virus hit the wild, spawning a family of
malicious attacks that would span the next nine months, anti-virus experts are on daily
watch for the next vicious attack.
Sobig-A, the first in a run of six variants, hit the wild a year ago today, Jan. 9. The
malicious family would go on to be known as the fastest-spreading and the most financially
damaging virus in the history of computers. It also one of the earliest pieces of code to
mix a virus with spamming.
Sobig-F, which ran rampant across the Internet in August and early September, has gone down
in the history books as the most damaging virus to date. It reportedly caused $36.1 billion
At this point, MessageLabs, an anti-virus company based in New York, has intercepted 737,125
copies of Sobig in 183 countries. At its peak, one in every 17 emails stopped by MessageLabs
contained a copy of Sobig-F, the most malicious of the variants. By Dec. 1, more than 32
million emails containing the virus had been stopped by the company, easily putting Sobig-F
at the head of various Top 10 Viruses list for 2003.
During Sobig-F’s rampage across the Internet, AOL saw email traffic nearly quardruple ,
according to an earlier interview with Nicholas Graham, an AOL spokesman. Graham says AOL
scans email attachments at the gateway, checking for viruses. On an average day, the ISP
scans approximately 11 million attachments. One day during the Sobig-F attack, the staff
scanned 40.5 million email attachments and found 23.7 million of those to be infected with
viruses. Of those, 23.2 million were infected with Sobig-F.
Sobig is a mass-mailing worm that can also spread via network shares. When it arrives via
email, the worm poses as a .pif or .scr file. The sender’s address is spoofed. The worm also
has updating capabilities and will attempt to download updated versions when certain
conditions are met.
The Sobig variants were hitting the wild in fairly fast succession. Each variant carried
code that would kill the virus off on a certain date, specifically limiting the variant’s
lifecycle. Soon after one variant died off, another one would emerge to take its place,
building on the impact of its predecessors.
Earlier variants of Sobig infected computers and then downloaded Trojans to set the machines
up to be hidden proxy servers. With each variant, the author had a bigger army of machines
set up for the next seeding.
After Sobig-F died out on Sept. 10, anti-virus and security experts were waiting with baited
breath for the next variant, or Sobig-G, to hit within a matter of days. It didn’t, and it
still has yet to hit the wild.
”I am fairly surprised about that,” says Chris Belthoff, a senior security analyst at
Sophos, Inc., an anti-virus company based in Lynnfield, Mass. ”It could be that the author
or authors of Sobig are running a little scared. It was such a widespread and damaging
virus, and now he has the Microsoft bounty on his head. This person or persons may be lying
low out of fear. He might have been too successful for his own good.”
Microsoft Corp. announced in November that it is putting a quarter-of-a-million-dollar
bounty on the heads of the virus writers behind the highly destructive Blaster and Sobig
worms. The rewards are part of a $5 million fund that Microsoft set aside to battle
malicious code and the hackers and spammers behind it.
But just because the author of Sobig may be laying low right now, it doesn’t mean that the
security industry isn’t waiting for the next destructive variant to hit.
”We’re always waiting,” says Belthoff. ”We’re always expecting that one day it will
appear in our lab. We’re always on guard.”