Denial-Of-Service Attacks Common
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 U.S., the Computer Emergency Response Team Coordination Center 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 sites servers bog down while responding to the messages, and sometimes crash. "Some sites merely experience bad performance, but thats 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, Microsofts Hotmail and the White Houses site. The attacks took place all over the world, not just in the U.S.
Asta Networks, which also supplies software to protect against denial-of-service attacks, co-sponsored the study.