Most SSL Sites Poorly Configured

BLACK HAT USA -- Las Vegas -- The good news about SSL-based websites: Most are running strong encryption. The bad news: More than 60 percent aren't properly configured.

Researcher Ivan Ristic, who is director of engineering, Web application firewall, and SSL at Qualys, revealed findings here yesterday from a study he conducted of some 120 million registered domain names. Ristic found that 20 million of them support SSL, but only 720,000 of these have potentially valid SSL certificates. "That's a very small percentage, but it doesn't really mean anything apart from that a fraction of sites use SSL, which we've known," Ristic say.

Of the more telling findings was that of all the SSL sites, half use SSLv2, an older version of SSL, which is known to be insecure. Only 38 percent of all SSL sites are actually configured well, Ristic says, and 32 percent contain a previously exposed renegotiation vulnerability in the protocol.

Meanwhile, researchers Robert "RSnake" Hansen and Josh Sokol here yesterday detailed some 24 exploitation techniques possible against HTTPS/SSL for browsers that leverage man-in-the-middle (MITM) attacks. Among them: cookie poisoning and injecting malicious content into browser tabs. The researchers warned that HTTPS can't guarantee confidentiality and integrity in the browser.

"The sky is not falling ... but SSL is pretty frail right now," Hansen said in the presentation. "There needs to be proper tab isolation, cookie sandboxing, and proper padding and jitter, and a lot of this goes away," however, he says. Hansen recommends using a separate browser for sensitive browsing.

Ristic, meanwhile, says while the state of SSL websites is "average" in terms of security, SSL is rarely targeted by attackers today. "I have a disclaimer: SSL is not a common attack vector today because there's so much low-hanging fruit out there. I think it's the time to start fixing things, and they can be fixed."

Two-thirds of the SSL sites use default settings, which leave them open to attack. "To fix this, you have to raise awareness and reach end users or talk to the vendors and see if they can make the defaults better, which is probably the more feasible [solution]," Ristic says. Leaving default support for insecure protocols, for example, in SSL servers is one common mistake.

"To configure an SSL server well is a 15-minute job. You choose the key size for the cert, disable the insecure protocols, and disable the insecure ciphers."

And while the insecure SSLv2, which is susceptible to MITMattacks, has been disabled in most major browsers, Ristic says, it's still running many SSL websites. "The saddest thing was that more than half of all of them support SSL2. We've known that to be insecure for years."

There was little or no support in the more secure TLS 1.1 and 1.2 protocols in the SSL websites, he found.

But most SSL websites use strong encryption -- 128-bit and higher, the study found. Overall, Ristic says only 38.4 percent of SSL websites got an "A" for their security and configuration, while 61.46 percent got a B or lower. Ristic plans to go public with all of the data from the survey, and to run the survey on an annual basis.

Jeff Moss, founder of Black Hat, during the keynote here called SSL "broken" and said while some security problems have been addressed, it still has a ways to go.

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