Apple has secretly added a new security feature in iOS 18.1 that causes iPhones to reboot after a period of inactivity. The new iOS 18.1 feature, called Inactivity Reboot, was discovered after a report by 404 Media, which described how iPhones confiscated by law enforcement were randomly rebooting.
The cops had speculated that iPhones were communicating with each other to reboot. This was causing an issue as it was locking them out, making them impossible to crack and open.
At the time, several outlets speculated that this might be a new iOS 18 feature secretly added by Apple. However, there was also a bug in iOS 18 that was causing iPhones to restart themselves.
I thought the phenomenon reported by the cops was caused by the latter, but I now have to hold my hands up — pun intended — and admit I was wrong. 404 Media has now written a follow up confirming the feature was quietly added by Apple in iOS 18.1.
Security researcher Jiska Classen dug into Apple’s code and discovered the new iOS 18.1 feature, detailing it on Mastodon.
“Apple added a feature called “inactivity reboot” in iOS 18.1,” Classen wrote. “This is implemented in keybagd and the AppleSEPKeyStore kernel extension. It seems to have nothing to do with phone/wireless network state. Keystore is used when unlocking the device. So if you don’t unlock your iPhone for a while… it will reboot!”
Rebooting your iPhone makes it more secure because it puts it into a state known as Before First Unlock (BFU), where information is encrypted and Face ID disabled until a user enters a passcode.
Inactivity Reboot In Action
In iPhones updated to iOS 18.1, the Inactivity Reboot feature will reboot your device after it has sat idle for four days. Doing this makes your iPhone almost impossible to crack, even with the sophisticated tools used by cops.
It is “impressive” that Apple is “baking in preventative measures to help keep devices more secure,” says Jake Moore, global cybersecurity advisor at security outfit ESET.
However, Moore, who previously worked for law enforcement forensically examining devices, thinks the feature “will frustrate every police force around the world.”
“It is right that Apple is doing more to secure phones and keep them safe post theft, but this will also potentially mean some police evidence will now never be located which will have an impact on criminal proceedings,” he says.
iOS 18.1’s Inactivity Reboot Builds On Stolen Device Protection
The Inactivity Reboot feature builds on Apple’s Stolen Device Protection, which helps to stop thieves from getting hold of your iPhone data.
It’s a great new feature that helps boost iPhone security for people who’ve updated to iOS 18. It’s therefore a little odd that Apple hasn’t been promoting it openly.
Even so, it’s a reason to update to iOS 18, to add that little bit of extra security to your device should it get lost or stolen.
