Applying Offensive Reverse Engineering to Facebook Gameroom
Late last year, I was invited to Facebook's Bountycon event, which is an invitation-only application security conference with a live-hacking segment. Although participants could submit vulnerabilities for any Facebook asset, Facebook invited us to focus on Facebook Gaming. Having previously tested Facebook's assets, I knew it was going to be a tough challenge. Their security controls have only gotten tougher over the years – even simple vulnerabilities such as cross-site scripting are hard to come by, which is why they pay out so much for those. As such, top white hat hackers tend to approach Facebook from a third-party software angle, such as Orange Tsai's well-known MobileIron MDM exploits.
Given my limited time (I also started late due to an administrative issue), I decided to stay away from full-scale vulnerability research and focussed on simple audits of Facebook Gaming's access controls. However, both the mobile and web applications were well-secured, as one would expect. After a bit of digging, I came across Facebook Gameroom, a Windows-native client for playing Facebook games. I embarked on an illuminating journey of applying offensive reverse engineering to a native desktop application.