November 28, 2001, 2:56 PM — It's that time of year again: Get ready for 2001 "Top 10" lists. In one of the first to come out this year, antivirus company Sophos PLC released its annual list of the top 10 viruses for 2001, with the Nimda worm taking honors as the most destructive worm or virus of the year.
Nimda accounted for 27 percent of all reports received by Sophos' help desk during 2001, with the Sircam virus making up 20.3 percent of all reports for the year, according to Graham Cluley, senior technology consultant at Sophos.
In its report, Sophos uses the term "virus" to cover viruses, worms and Trojan horses. While viruses and worms are both destructive or disruptive programs, the main difference between the two is that the distinct computer code in a worm can spread unaided whereas a virus needs a program or an end user's aid to perpetuate itself. A Trojan horse has its malicious or harmful code inside programming or data that appears to be harmless and once inside a PC hard drive, can take control and do the damage it is intended to do.
Nimda and Sircam made up almost half of all virus attacks reported to Sophos, according to Cluley. "So far this year, we've detected 11,160 new viruses, worms and Trojan horses, which just about brings the virus total to 70,000. In general, there are about 40 new viruses a day, 1,200 every month. About 30 to 40 of those virus break into what we call 'the wild' each month and cause serious problems," Cluley said.
At number three was Magistr with 12 percent of all reported infections, followed by Hybris with 6.2 percent, Apology with 3.8 percent, VBSWG-X with 3.6 percent, Kakworm with 3.1 percent, SST-A with 2 percent, Badtrans with 1.8 and Navida rounded out the list at number 10 with 1.8 percent, Cluley said. The remaining 18.2 percent of reported infections came from a variety of smaller viruses, he said.
Sophos has offices in the U.K., U.S., Australia, France, Germany, Italy, Japan and Singapore and as a result has a good idea of which viruses are attacking where, Cluley said.
When asked if the list may be premature, in that the current number nine, Internet worm Badtrans, may wreak havoc in December, Cluley conceded that the list is released at the end of November every year so that various magazines can include the list in their publications.
"Badtrans does appear to have legs and it is the most common worm, or virus to use the term generally, at the moment. But at the same time, it is not as big as Nimda and Sircam were at the same stages of their emergence (on the Internet)," Cluley said.
Cluley pointed out that no viruses attacked PDAs (personal digital assistants) or mobile phones in 2001, despite a lot of worry in the media to the contrary. Also in 2001, the most dangerous worm of the year, Nimda, could itself have been largely avoided.