Apple’s new USB Restricted Mode had been released with the iOS 11.4.1 release yesterday, and it seems that it may not be as secure as it was previously believed.
The feature is designed to protect iPhones against USB devices that are used by law enforcement in order to crack users’ passcodes.
It works by disabling USB access after the phone has been locked for about an hour.
There’s a loophole in the security feature
The computer security company called ElcomSoft managed to find a loophole.
The company’s researchers have found that the one hour counter will be reset if you decide to plug in a USB accessory within the window.
It also seems that it doesn’t matter whether the accessory has ever been used with the phone in the past.
The tests have shown that that bypass even works with Apple’s own Lighting to USB 3 camera adaptor.
ElcomSoft is currently in the process of performing even more tests on other adaptors.
According to Oleg Afonin, “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.”
He also questioned the chances of a device being seized within an hour after its last unlock.
“Quite high. We were not able to find any recent stats, but even two years ago an average user unlocked their iPhone at least 80 times a day,” he claims.
The issue was not created on purpose
On the other hand, ElcomSoft says the ability to postpone Restricted Mode by connecting an iPhone to an untrusted USB accessory is “probably nothing more than an oversight.”
Apple introduced the Restricted Mode feature in the first place to keep off law enforcement access, and considering this, it seems really unlikely that they would include such a loophole on purpose. We can’t tell yet what Apple’s next step will be in order to fix this.