DoS attacks becoming commonplace

A researcher at the University of California at San Diego has documented that denial-of-service attacks are commonplace on the Internet, with an average of 4,000 occurring each week during a recent three-week study.

As if to underscore the point, one of the most prominent security sites in the US, the Computer Emergency Response Team Coordination Centre at Carnegie Mellon University, was brought down by a denial-of-service attack last week. The CERT center, ironically, is the primary source for Internet security threat warnings.

Denial-of-service attacks use multiple "zombie" servers, captured by intruders, to launch thousands of messages per second at a given target. The site's servers bog down while responding to the messages, and sometimes crash. "Some sites merely experience bad performance, but that's a big deal to a service provider," said Ted Julian, chief strategist at Arbor Networks, which offers a hardware/software system for countering denial-of-service attacks.

The study found that recent targets included Amazon.com, Microsoft's Hotmail and the White House's site. The attacks took place all over the world, not just in the US. Asta Networks, which also supplies software to protect against denial-of-service attacks, cosponsored the study.

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