Rodney Thayer, a researcher at security consulting firm Canola & Jones, is working on a paper about SSL vulnerabilities that will be presented at the Chaos Communication Camp (CCC) hacker conference in Berlin at the end of this month. The paper outlines the results of tests he conducted using simple search engines and his knowledge of cryptography and SSL certificates.
"I started out thinking I might do something like the "month of Apple flaws," where I talked about a new one each day," Thayer says. "But as I looked at everything I found, it seemed important enough that I wanted to get it out there more quickly."
So during the course of two days, Thayer documented SSL implementation issues on 31 major sites -- one for each day of the month. "There could have been a lot more," he says. "What I've found is that if you give me a Web browser and about 10 minutes, I can find you a broken [SSL] certificate." Thayer is currently conducting a process of vetting the vulnerabilities with other researchers and informing the sites involved, as is prescribed under the rules of responsible disclosure.
Although the paper outlines 31 different SSL issues, many of the problems are of a common ilk, Thayer says. One of the most common is configuration error. "I saw a lot of retail sites, for example, that offer users access to both www.store.com and then just store.com," Thayer says. "They may think they're making things more convenient for the user, but that sort of thing can really wreck the functionality of SSL certificates."
In many other cases, Thayer found sites that were operating on expired certificates or were using outdated technologies, such as SSL 2 or the 40-bit RC-4. "There's absolutely no reason why anybody should be using SSL 2, which has proven to be vulnerable," he says. "And in most cases, using RC-4 would be a reason for a retailer to fail a PCI audit. These are technologies that shouldn't be out there anymore."
While much of the blame for these faults lies with the companies who operate the Websites, the research also suggests there may be a strong need for better standards and practices among SSL certificate authorities, Thayer says.
"In my research, I found something like 247 certificate authorities that are considered to be legitimate, ranging from the best-known authorities like VeriSign to some small organization in Turkey that will provide certificates for free," Thayer says. "There are no real industry standards for what constitutes a certificate authority."
And in most cases, the certificate authorities don't have a process for continually testing the validity of SSL certificates and warning sites when they fall out of line. "I understand that they can't check every site, but when they're acting as the authority for a company that has 300 different certificates, they should have a way to say, 'Dude, you're out of line,'" Thayer says.
Enterprises should be checking the validity of their SSL certificates on a regular basis, either through internal testing or external penetration tests, Thayer advises. "You can do it yourself by going across the street to Starbucks and checking to see that your certificates are working properly," he says.
End users should also be aware that not every SSL connection is completely safe. "Don't ignore the popups and the warnings that you might see in your browser," Thayer says. "Check your SSL connections and make sure they're working before you start sending sensitive data."
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