The evasi0n7 jailbreak was released by the evad3rs on 22nd December 2013 targeting 7.0 to 7.1b3 iOS devices (iDevices). This talk documents the reverse engineering process of evasi0n7's main kernel exploit, which was performed in order to not only understand the underlying vulnerability, but more importantly to document the exploitation techniques the evad3rs have utilized. The talk will initially focus on the kernel debugging setup (a very important but often ignored step in device/embedded exploitation talks), the encountered problems and how they were overcome. I will then explain the underlying vulnerability, and the reverse engineering of the implemented exploitation techniques. Finally, I will present a detailed step by-step re-implementation of the kernel exploit.