Apple quietly introduced code into iOS 18.1 which reboots the device if it has not been unlocked for a period of time, reverting it to a state which improves the security of iPhones overall and is making it harder for police to break into the devices, according to multiple iPhone security experts.
On Thursday, 404 Media reported that law enforcement officials were freaking out that iPhones which had been stored for examination were mysteriously rebooting themselves. At the time the cause was unclear, with the officials only able to speculate why they were being locked out of the devices. Now a day later, the potential reason why is coming into view.
“Apple indeed added a feature called ‘inactivity reboot’ in iOS 18.1.,” Dr.-Ing. Jiska Classen, a research group leader at the Hasso Plattner Institute, tweeted after 404 Media published on Thursday along with screenshots that they presented as the relevant pieces of code.
Great explanation. That was super insightful.
So even with BFU, does the iPhone not connect to the internet? I guess i hadn’t noticed it doesn’t.
Also are you still about to track via gps an iPhone that is in the off state? Just curious if there’s a lot of other vectors where the iPhone is still connected?
Well, it’s complicated. Most of these topics are. In BFU state, an iPhone (or iPad with cellular) with an active SIM and active data plan will connect to the Internet. It won’t connect to Wi-Fi at all. If you have USB restricted mode disabled and the right accessory connected it will connect to an Ethernet network, but that may fail if the network requires 802.1x and the credential is not available in BFU state. Similarly if USB restricted mode is disabled you can use tethering to a Mac to share its network.
For location, there’s two mechanisms. One mechanism relies on directly communicating with the device, which only works if the device has network.
The other mechanism is the “FindMy network” which uses a Bluetooth low energy (BTLE) beacon to let other nearby devices detect it, and they report that to FindMy. It’s a great technology. The way it uses rotating IDs preserves your privacy while still letting you locate your devices. I know that this works when a device is powered off but the battery is not completely dead. I’m not sure if it works in BFU state… my guess it that it does work. But this is not networking. It’s just a tiny Bluetooth signal broadcasting a rotating ID, so it’s one-way communication.
Other than that, I’m not as sure how things work. I believe Bluetooth is disabled by default in BFU state, but I suspect users can choose to re-enable Bluetooth in BFU state to connect to accessibility accessories. I’m not sure about the new emergency satellite communication.
But one thing I know for sure is that Apple has world class security engineers, and one area they work hard to secure is devices in BFU state.