Dasient, a Web security startup founded by engineers and product managers from Google and McKinsey, on Tuesday plans to begin open beta testing of its new Web Anti-Malware (WAM) service.

Neil Daswani, co-founder of the company, used to work as a Web security engineer and product manager at Google. He started Dasient with Ameet Ranadive from McKinsey and Shariq Rizvi from Google to address changing malware distribution patterns and to provide a way to respond to Web threats using automated mitigation techniques.

Legitimate Web sites have become unwitting malware distribution points, thanks to poor Web application security. During the second half of 2008, 77% of Web sites spreading malicious code were legitimate sites that had been hacked, according to Websense Security Labs.

According to Daswani, malware authors will scan for vulnerable versions of a particular Web application and then run automated scripts to infect every vulnerable application identified.

This not only makes dealing with the problem difficult because so many Web sites are affected, but it also raises the possibility of being blacklisted by search engines, browser makers, and/or security companies.

And once a Web site is blacklisted, Web visitors arrive far less frequently or stop arriving altogether. Blacklisting essentially strangles ad revenue.

Web site owners have long complained about how difficult it can be to get off a blacklist. Dasient aims to prevent Web sites from ever being blacklisted or at least to keep the time spent on a blacklist to a minimum.

The company is offering a free blacklist monitoring service, to alert site owners when their sites have become infected, and a premium monitoring and diagnostic service for alerting site owners and supplying them with information about any malware found, to make remediation easier. Both the free and the premium service are now available as part of a public beta test.

The company is also offering an additional level of protection, a quarantine service that blocks malicious code on Web pages while still serving those pages to visitors. The quarantine service is still in private beta testing. Interested parties can sign up at the Dasient Web site.

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