Slides of Zdziarski’s talk, titled Identifying Back Doors, Attack Points, and Surveillance Mechanisms in iOS Devices are here.
Also check the page about iOS: About diagnostic capabilities on Apple Support:
Each of these diagnostic capabilities requires the user to have unlocked their device and agreed to trust another computer. Any data transmitted between the iOS device and trusted computer is encrypted with keys not shared with Apple. For users who have enabled iTunes Wi-Fi Sync on a trusted computer, these services may also be accessed wirelessly by that computer.