https://threatpost.com/researcher-identifies-hidden-data-acquisition-services-in-ios/107335
Found this on another site and thought it was pretty interesting, basically there's some services in iOS that can "be used to bypass the backup encryption on iOS devices and remove large amounts of users’ personal data."
I found this bit particularly interesting:
"Some of the undocumented services and features in iOS map pretty closely to capabilities attributed to some of the NSA’s tools, specifically DROPOUTJEEP, which was revealed by documents leaked by Edward Snowden.Zdziarski said that he is not pointing to these services as intentional backdoors for the intelligence community, but he believes there is evidence that the agency may be using them, nonetheless."