Last November Reginaldo Silva, a computer engineer in Brazil, found one of the worst kinds of vulnerabilities in Facebook's software. It has netted him the biggest bug bounty the social network has ever paid out, but while he's not complaining, it wasn't quite the windfall he hoped for.
The bug related to code used for OpenID, an authentication system that lets people use the same login credentials for multiple online services.
Silva found that the vulnerability could be executed from a remote computer, one of the most dangerous types of software flaws. It could have allowed a hacker to read almost any file and open arbitrary network connections on a Facebook server.
"I knew I had found the keys to the kingdom," Silva wrote on his blog.
Facebook didn't reveal in its own blog post Wednesday how much it paid him for finding the bug, saying only that it was the company's "biggest bug bounty payout ever." But with Silva's permission, a Facebook spokesman later revealed that the amount was $33,500.
Silva gently noted in his blog something that Facebook's director for Security Incident Response reportedly said in July 2012. Bloomberg quoted the director, Ryan McGeehan, as saying, "If there's a million-dollar bug, we will pay it out."
That got Silva's hopes up, especially after Facebook told him his payout would be raised since the bug he found was a remotely executable one.
"I won't disclose the amount, but if you have any comments about how much you think this should be worth, please share them," Silva wrote in his blog post. "Unfortunately, I didn't get even close to the $1 million dollar payout cited above."
Facebook has concluded that no one exploited the flaw. A thriving underground market exists for such information, though it's difficult to put a price on it. If millions of Facebook users' data had been compromised, the backlash could have been costly and hurt the social network's reputation.
Silva notified Facebook of the flaw on Nov. 19. The social networking site said Wednesday it had alerted on-call employees and pushed out a short-term fix in just three and a half hours.
Facebook pays a minimum of $500 for a vulnerability that qualifies under its terms and conditions. There is no maximum reward, it says in its information about bug bounties: "each bug is awarded a bounty based on its severity and creativity."
The bug, which Silva found in September 2012, wasn't unique to Facebook; he found it had affected other web services, including two Google services: App Engine and Blogger. After alerting Google to the issues, he decided to see if Facebook was affected too.
Silva wrote there are many servers on the Internet that are still vulnerable, which is why he didn't publish proof-of-concept code that would show how the flaw could be abused.
Google awarded him $500 for pointing out the issue, Silva wrote. He posted the technical details in his write-up.
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