University of California-San Diego Professors Geoff Voelker and Stefan Savage said 94 percent of spam-advertised scams are hosted on individual Web servers. That discovery, they said, should aid in reducing the volume of spam and close illegal online businesses and malware sites.

Using new Internet monitoring approaches developed at UCSD, the scientists analyzed spam-advertised Web servers hosting online scams that either offer merchandise and services or use malicious means to defraud users, such as phishing and spyware.

The researchers followed the URLs embedded in the spam back to the hosting servers, probed the servers and analyzed the Web pages advertised in the spam.

“A given spam campaign may use thousands of mail relay agents to deliver its millions of messages, but only use a single server to handle requests from recipients who respond,” Voelker and Savage said. “A single takedown of a scam server or a spammer redirect can curtail the earning potential of an entire spam campaign.”

The study was to be presented Thursday in Boston during the USENIX Security 2007 conference.