Security threats Toolkit

Spam-seeding viruses dominate August charts

Matt Loney ZDNet.co.uk

Published: 01 Sep 2004 16:37 BST

The number of new viruses released onto the Internet reached a 33-month high during August, but infections were dominated by old-timers that were used primarily to seed networks for spammers.

In their virus reports for August, software and Internet security companies said that viruses such as Netsky, Zafi and MyDoom, together with their variants, continued to dominate the charts.

"Although we have seen a small, 10 percent, decline in reports of Zafi-B since last month, this email-aware worm doesn't look like it's going to fade into obscurity anytime soon," said Carole Theriault, security consultant at antivirus firm Sophos. "Protection against Zafi-B has been available for a couple of months now, and computer users need to get into the habit of updating their systems in a much more timely manner, or this nuisance will continue to dominate reports."

Sophos analysed and protected against 1,230 new viruses in August, the highest number of new viruses seen in one single month since December 2001. "Despite more than 1,200 new viruses being detected in August, not one has made it into the chart this month," Theriault said. "The entire top 10 is made of viruses which have been doing the rounds for weeks if not months."

Email security outsourcing firm MessageLabs said the ratio of viruses to emails passing through its servers was 1 in 14 -- about the same as for July. The rate for June was one in 11. Spam interceptions meanwhile spiralled to 100 million for August, accounting for 70 percent of all email flowing through the company's servers. This is the largest number on record and about 25 percent higher than the figure for July.

Mark Sunner, chief technical officer at MessageLabs, said the trend for viruses to be linked to spam had continued. "Nearly all the viruses we see now are for propagating spam," said Sunner. "For instance, setting up open proxies. So the spammers will blast out viruses to seed a network for spamming, which ultimately dries up." Sunner said the seeding tends to happen in waves, repeating itself each quarter. July and August were relatively quiet for viruses, suggesting that September will be more active.

See next page for the top 10 threats according to antivirus companies.