Face.com, the facial recognition start-up recently purchased by Facebook, has patched a vulnerability in its KLIK application that could have enabled attackers to compromise Twitter and Facebook accounts.
The vulnerability was reported by independent security researcher Ashkan Soltani. KLIK is an iPhone camera app designed to make it easy for Facebook users to tag their friends in photos using facial recognition technology.
"I found an extremely basic vulnerability in…which the app allows access to other user’s KLIK information, including private ‘authentication tokens’ (i.e keys) for user’s Facebook & Twitter accounts (KLIK relies on Facebook to use the app)," Soltani blogged. "Face.com essentially allowed anyone to hijack a KLIK user’s Facebook and Twitter accounts to get access to photos and social graph (which enables 'face prints'), even if that information isn’t public."
According to Soltani, Face.com was storing Facebook/Twitter OAUTH tokens on their servers insecurely, allowing them to be queried for any user without restriction. Specifically, once a user signed up for KLIK, the app would store their Facebook tokens on Face.com’s server. Subsequent calls to https://mobile.face.com/mobileapp/getMe.json would return the Facebook "service_tokens" for any user, allowing the attacker to access photos and post as that user. If the KLIK user has linked their Twitter account to KLIK App, their 'service_secret' and 'service_token' was also returned.
"Given the nature of the technology (facial recognition), the privacy concerns are significant," he blogged. "The above attack not only allows access to non-public photos, but also lets the attacker potentially manipulate the Face.com app to automatically ‘recognize’ anyone walking down the street (i.e just hijack Lady Gaga’s and get her ~11 million friends’ ‘face prints’)."
In addition, the vulnerability allowed the attacker to hijack the account and post status updates and Tweets as that user, he wrote.