iOS Devices Can Be Blocked From Entering USB Restricted Mode

Oleg Afonin, writing for the ElcomSoft blog:

What we discovered is that iOS will reset the USB Restrictive Mode countdown timer even if one connects the iPhone to an untrusted USB accessory, one that has never been paired to the iPhone before (well, in fact the accessories do not require pairing at all). In other words, once the police officer seizes an iPhone, he or she would need to immediately connect that iPhone to a compatible USB accessory to prevent USB Restricted Mode lock after one hour. Importantly, this only helps if the iPhone has still not entered USB Restricted Mode.

Most (if not all) USB accessories fit the purpose — for example, Lightning to USB 3 Camera Adapter from Apple.

They think this might be tricky for Apple to fix:

Can Apple change it in future versions of iOS? To us, it seems highly unlikely simply because of the humongous amount of MFi devices that aren’t designed to support such a change. Theoretically, iOS could remember which devices were connected to the iPhone, and only allow those accessories to establish connectivity without requiring an unlock — but that’s about all we can think of.

★ Wednesday, 11 July 2018