Researchers with the Web Application Security Consortium (WASC) are hitting Web attackers and spammers where they live and hide out -- in open Web proxy servers. According to the latest findings by WASC, banner ad/click-fraud and spam ranked as the most common traffic visiting the organization's honeynet of decoy proxy servers for tracking real Web attacks.

Open proxies are an attacker's camouflage, providing them with anonymity in their requests to the Web. WASC's honeynet researchers are basically using the attackers' own tool against them, with fake open proxies in the honeynet. "I know that attackers use open proxies, so you can't always track them down. So I turned the tables on them," says Ryan Barnett, an officer with WASC and director of application security training for Breach Security.

Barnett, who heads up the WASC honeynet project, says the researchers have put in controls so that attackers can't loop through the honeynet to attack other sites, however. "If the traffic is normal or benign, we do proxy it through and it goes to its destination. If we see a live attack, we block it, and also spoof back some information to the attacker, such as HTTP status codes," Barnett says. "We want to see what the bad guys are really doing" in their Web attacks, he says.

Of the 9 million Web requests that hit the WASC honeynet in October, more than 2 million contained malicious, known attacks or other suspicious behavior. The global honeynet of Apache proxy servers configured with VMware was set up in January, and contains 15 of Breach Security's ModSecurity Web application firewalls, which identify, block, and log the attack traffic. The servers sit as decoys, gathering attack data that's monitored by the WAPs.

Banner add/click-through fraud traffic accounted for 2.6 million requests in October alone -- a major jump from 158,000 in the period between January and April of this year. And spammers weren't far behind, with nearly 2 million requests to the WASC honeynet proxies last month. That number was up from nearly 110,000 in the first phase of the project.

"And the bad guys are using automation as well," Barnett says.

This automated approach is all about brute-force attacks, he says. "Forget the bad guy just going to a porn site. With brute force, it's only a matter of time before they break into" legitimate sites, he says.

One method attackers are using is distributed reverse-brute force authentication, where an attacker scans a popular email provider's accounts in search of user names. "They are using common passwords and cycling them through different user names that might use them," Barnett says. That reverse method -- trying to crack the user name instead of the password -- lets them evade detection and prevents them from getting locked out of an account.

Barnett says he and his fellow researchers have also witnessed spammers using "Google-hacking" to search for blogs and to identify targets. "Then they are sending spam messages to user forums and blog postings."

And WASC says it found evidence that there are numerous legitimate Websites with malicious JavaScript code implanted in them, which targets unpatched browser vulnerabilities and then installs malware onto the victim client's machine. "It used to be if you didn't go to gambling or Warez sites, you were okay, but we're seeing more and more that that's not the case," Barnett says. "Legitimate sites are getting malware injected into them."

Websites are also suffering from "information leakage," where they provide too much detail in error messages, which can give the attacker valuable information about vulnerabilities in the site that he or she could use to wage an attack, according to WASC, which will present its findings today at the Open Web Application Security Project (OWASP) & WASC AppSec 2007 Conference in San Jose, Calif.

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