IRS scam now world's biggest e-mail virus problem

Criminals are waging a nasty online campaign right now, hoping that their victims' fears of the tax collecter will lead them to inadvertently install malicious software.

The spam campaign, entering its third week now, is showing no signs of slowing down, according to Gary Warner, director of research in computer forensics with the University of Alabama at Birmingham. This one campaign accounts for about 10 percent of the spam e-mail that his group is presently tracking, he said. "This is the most prominent spam-delivered virus in the world right now," he said.

Since first spotting the spam on Sept. 9, antispam vendor Cloudmark has counted 11 million messages sent to the company's nearly 2 million desktop customers, said Jamie Tomasello, abuse operations manager with Cloudmark. That number is "very high," she noted.