New Method IDs Phishing, Malicious Domains

At a closed-door security summit hosted on Yahoo’s Sunnyvale campus last week, a researcher demonstrated a new technique to more easily identify phishing and other malicious Websites.

Dan Hubbard, vice president of security research for Websense, showed a tool Websense researchers have built that detects domains that were automatically registered by machines rather than humans -- a method increasingly being used by the bad guys, he says. “[Automation] is being used more and more,” Hubbard says.

Not much of the contents of the so-called ISOI conference typically seeps beyond the confines of this annual closed-door event: It’s set up to accommodate the privacy and sensitivity of the content and information shared, as well as the attendees themselves. But some participants, including Hubbard, were willing to discuss some elements of the ISOI 4 summit.

In case you were wondering how long it takes for stolen data to actually get exploited, some researchers at the ISOI4 reported that there’s about a five-hour window once a phishing site goes up to tear it down before the bad guys start using the stolen data, which is typically credit card numbers.

Meanwhile, Websense’s new Lexi-Rep tool , which it uses internally in its Web security research, gives researchers -- and eventually, maybe domain registrars -- a way to sniff out any suspicious domains that get automatically set up. “Increasingly, we’re seeing more bots, keyloggers, and Trojans automatically connecting to domains,” Hubbard says. “And people are now automatically registering these domains without a human involved.”

The tool’s algorithm determines whether a domain name was registered by man or machine, by assessing whether the domain and URL are “human consumable,” or “whether someone would type that into a URL or search for that” site. It scores the likelihood of maliciousness of the domain and host name based on patterns in the name.

So while users may not notice that a phony “eBay.com” URL has a wild mix of random letters and numbers appended to it since the entire URL may not show up in their browser, this algorithm is aimed at nabbing any likely suspects. The pair of letters such as “JX” or “JW” in a domain, for example, are less likely to be paired together in English lexicon than, say, “TH.” “’TH’ would score very high because those two letters are likely to appear together, but ‘JW’ and ‘JX’ are not, so they would get a negative score,” Hubbard says. The algorithm weighs the scores and categorizes the sites, and sends some out for further analysis if needed.

The “bad” domain names then get blacklisted. Hubbard says the tool has an a 99.9 percent rate of accuracy, and that automatically generated domains to date represent over 1 percent of the nearly 1 million domains registered each day, but that share is rising.

Hubbard says Websense is happy to share the tool with domain registrars if they are interested in it -- it’s avoiding going the open source route because it doesn’t want the technology falling into the hands of the bad guys, who then could figure out how to circumvent it.

“I can see how this approach can help alert on some flavors of the domains phishers may register,” says Nitesh Dhanjani, a researcher who, along with fellow researcher Billy Rios, recently infiltrated the phisher community to get an inside look at how it operates. “However, phishers often set up their sites on compromised hosts and use the existing domain name structures, and they also use approaches that are hard to reduce into specific patterns. So although this sort of an automated approach will have positive impact, it shouldn't be the only technique businesses rely on to find out the URLs where phishing sites targeting them have been set up.” (See Researchers Expose 'Stupid Phisher Tricks'.)

Hubbard noted that data such as history of the IP, network, ASN, registration details, site content, search results, and email volumes, can also be factored in with a domain's scoring.

Meanwhile, Gadi Evron, one of the organizers of the ISOI 4 summit, says law enforcement, researchers, and the industry are getting better organized in fighting cybercrime, but they still have a ways to go. “We’re not really affecting the business of the criminals,” Evron says -- the key is to move past a reactive approach to threats.

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