Facebook today denied that it may have accidentally exposed personal user data to advertisers and other third parties for several years, as claimed this week by two security researchers at Symantec Corp.
The researchers in a blog post Tuesday noted that a Facebook programming error -- since fixed -- could have allowed advertisers to access member profiles, photographs and chat messages and to post messages and mine personal data from them.
According to Symantec, the leaks stemmed from a faulty API used by developers of Facebook applications. It caused "hundreds of thousands" of Facebook applications to accidentally expose the so-called access tokens that are granted by users to Facebook applications. "Each token or 'spare key' is associated with a select set of permissions, like reading your wall, accessing your friend's profile, posting to your wall, etc.," the researchers said.
Any third party or advertiser associated with an application developer that had used the faulty API would have had access to the tokens, allowing them to perform whatever actions the tokens allowed. While it's unclear how many advertisers even knew what was going on, the potential repercussions of the data leaks are "far and wide," Symantec claimed.
But Facebook downplayed the issue and argued that Symantec's report has a "few inaccuracies."
"We appreciate Symantec raising this issue and we worked with them to address it immediately," Facebook spokeswoman Malorie Lucich said in an emailed comment. But, "specifically, no private information could have been passed to third parties, and the vast majority of tokens expire within two hours," she said.
"The report also ignores the contractual obligations of advertisers and developers, which prohibit them from obtaining or sharing user information in a way that violates our policies," Lucich said.
She added that Facebook has no evidence of information being used in a way that violates company policies. "We take any potential issue seriously and quickly took steps to prevent this from happening again."
A Symantec spokesman this afternoon said the company still believes its original report is accurate, but did not comment further.
Kevin Haley, director at Symantec security response said that while it's likely that third-parties had not noticed the leak, it would be hard to say for sure whether someone noticed it and took advantage of it.
The issue is unlikely to improve Facebook's already battered reputation on the privacy front. The company has been at the center of numerous privacy related issues over the past couple of years.
Last October, for instance, the company found itself in the middle of a major firestorm after the Wall Street Journal reported that several popular Facebook applications such as FarmVille, Texas HoldEm Poker and FrontierVille had been secretly sending user information to advertisers.
Last year, the company was also hit with a lawsuit after some members claimed that changes the company made to its privacy settings made it even harder for users to control access to their personal data.
"This breach does not surprise me, because I've seen its like before in Facebook and in other Web sites [and] platforms," said Chris Palmer, technology director at the Electronic Frontier Foundation. "Although this bug might quite likely be an accident, it is not the first of its kind in Facebook."
Providing advertisers with detailed profiles of Facebook users has been part of Facebook's business model, he said. "Therefore we can expect for this kind of security failure to arise again," he said. "The business model requires Facebook to walk a fine line between keeping advertisers happy and not angering too many users."
Jeffrey Chester, executive director of the Center for Digital Democracy (CDD), said Facebook is working with a growing list of third parties who are in the business of collecting Facebook user information. "The company has the data collection for ad targeting spigot turned on -- so it's not a surprise that user information is leaking out to the others," Chester said.
Jaikumar Vijayan covers data security and privacy issues, financial services security and e-voting for Computerworld. Follow Jaikumar on Twitter at @jaivijayan or subscribe to Jaikumar's RSS feed. His e-mail address is email@example.com.
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