Vulnerable iOS and Android apps build on the Facebook SDK and leverage Facebook for user authentication. Once the app has successfully authenticated to Facebook, a local session token is cached and used to authenticate future sessions. The insecure storage of this session token is what places apps using the Facebook SDK for user authentication at risk of session hijacking.
The Facebook SDK is one of the most popular integrated libraries used by free and fee-based app developers for iOS and Android platforms. Specifically, MetaIntell has identified that 71 of the top 100 free iOS apps use the Facebook SDK and are vulnerable, impacting the over 1.2 billion downloads of these apps. Of the top 100 Android apps, 31 utilize the Facebook SDK and therefore make vulnerable the over 100 billion downloads of those apps.
Chilik Tamir, chief architect, research and development for MetaIntell, identified and duly named this flaw in both the Facebook SDK for iOS and Facebook SDK for Android. “It’s difficult to quantify the pervasiveness of this problem as not all iOS and Android apps utilize the Facebook SDK,” stated Tamir. “However, from our analysis, the SDK is widely used and given the type vulnerability, represents a substantial threat as it opens the door to imparting substantial damage to the reputations and brands of both individuals and organizations.”
MetaIntell discovered the vulnerability in May 2014 and Tamir and his team conducted further research to confirm it and evaluate the pervasiveness of the problem. The vulnerability along with research findings was reported to Facebook within two weeks of its initial discovery.
To mitigate the risk of the Social Login Session Hijacking vulnerability at this time, MetaIntell recommends iOS and Android device users discontinue use of the Facebook login by third party apps (get the details on how to do it here."
They recommend IT staff to alert their company employees about this vulnerability and advise them to discontinue using the Facebook login for apps.