Apple has added a brand new safety function with the iOS 18.1 replace launched final month to make sure that iPhones mechanically reboot after lengthy idle intervals to re-encrypt knowledge and make it more durable to extract.
Whereas the corporate has but to formally verify this new “inactivity reboot” function, legislation enforcement officers had been the primary to find it after observing suspects’ iPhones restarting whereas in police custody, as first reported by 404 Media.
This switches the idle units from an After First Unlock (AFU) state to a Earlier than First Unlock (BFU) state, the place the units are more difficult to interrupt utilizing forensic cellphone unlocking instruments.
Moreover, DFU makes extracting saved knowledge more durable, if not not possible, since even the working system itself can now not entry it utilizing encryption keys saved in reminiscence.
“Apple added a function referred to as “inactivity reboot” in iOS 18.1. That is applied in keybagd and the AppleSEPKeyStore kernel extension,” as Hasso-Plattner-Institut researcher Jiska Classen defined.
“It appears to don’t have anything to do with cellphone/wi-fi community state. Keystore is used when unlocking the system. So if you happen to do not unlock your iPhone for some time… it would reboot!”
Merely put, on iOS units, all knowledge is encrypted utilizing an encryption key created when the working system is first put in/arrange.
GrapheneOS instructed BleepingComputer that when an iPhone is unlocked utilizing a PIN or biometric, like Face ID, the working system hundreds the encryption keys into reminiscence. After this, when a file must be accessed, it would mechanically be decrypted utilizing these encryption keys.
Nevertheless, after an iPhone is rebooted, it goes into an “at relaxation” state, now not storing encryption keys in reminiscence. Thus, there is no such thing as a technique to decrypt the information, making it far more proof against hacking makes an attempt.
If legislation enforcement or malicious actors acquire entry to an already locked system, they’ll use exploits to bypass the lock display screen. Since decryption keys are nonetheless loaded into reminiscence, they’ll entry all the cellphone’s knowledge.
Rebooting the system after an idle interval will mechanically wipe the keys from reminiscence and forestall legislation enforcement or criminals from accessing your cellphone’s knowledge.
An Apple spokesperson was not instantly accessible for remark when contacted by BleepingComputer earlier.