A significant new Web attack, the latest in the genre of crimeware that threatens to turn highly trusted Web sites into insidious traps for unwary visitors, has been identified by Finjan’s Malicious Code Research Center (MCRC).

The attack designated “random js toolkit” by Finjan, is an extremely elusive crimeware Trojan that infects users’ machines and sends data via the Internet to the Trojan’s master.

Last month a security company named Finjan identified over 10,000 Web servers that were infected by “random js toolkit” even though the toolkit stores the IP addresses of Web crawlers that are used by security companies to examine Web pages. Web crawlers recognized by the toolkit are served legitimate content and therefore raise no red flags – it’s the rest of us “real people” visitors who’ll end up with the malware.

“You don’t need any security experience,” said Yuval Ben-Itzhak, Finjan chief technology officer. “You can just install it on the server and start to infect people with the Trojan horses.”

Finjan isn’t the only company with that kind of technology. Exploit Prevention Labs, which was recently acquired by security company AVG, also has a product called LinkScanner that analyzes Web page content for malware, and McAfee has a service called SiteAdvisor that ranks the health of a Web site. All three companies offer free versions of their products.