Apple has added a brand new safety function with the iOS 18.1 replace launched final month to make sure that iPhones routinely reboot after lengthy idle durations to re-encrypt knowledge and make it tougher to extract.
Whereas the corporate has but to formally affirm this new “inactivity reboot” function, regulation enforcement officers have 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 tougher to interrupt utilizing forensic telephone unlocking instruments.
Moreover, DFU makes extracting saved knowledge tougher, if not inconceivable, 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 telephone/wi-fi community state. Keystore is used when unlocking the machine. So when you do not unlock your iPhone for some time… it is going to 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 advised 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 is going to routinely 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 isn’t a option to decrypt the info, making it far more proof against hacking makes an attempt.
If regulation enforcement or malicious actors acquire entry to an already locked machine, they’ll use exploits to bypass the lock display screen. Since decryption keys are nonetheless loaded into reminiscence, they’ll entry all the telephone’s knowledge.
Rebooting the machine after an idle interval will routinely wipe the keys from reminiscence and stop regulation enforcement or criminals from accessing your telephone’s knowledge.
An Apple spokesperson was not instantly out there for remark when contacted by BleepingComputer earlier.