Oliver Haslam on July 18, 2018, 6:45 am

iOS 12 Beta 4 Makes USB Restricted Mode Instantly Active When Device Is Locked

With Apple already planning on implementing USB Restricted Mode in iOS 12, the arrival of iOS 12 beta 4 brings with it a tweaked version of the feature in an attempt to further thwart the use of GrayKey boxes, a device that is used to brute force iOS passcodes.

In previous iOS 12 betas, the USB Restricted Mode meant that users would need to enter their passcode in order to use data connection over the Lightning port if they had not authenticated within the last hour, although power would still pass through as normal.

This meant that if someone connected an iOS device to a GrayKey box and tried to brute force a passcode outside of that 60-minute window, they would be out of luck.

It was subsequently noted that even with this feature in place, it was possible to bypass USB restricted mode in some circumstances. This was due to the fact that the hour-long window was essentially reset by connecting a USB accessory to the device’s Lightning port.

With iOS 12 beta 4 installed, however, this is no longer the case with iOS devices requiring the entry of a passcode in order to be connected to a computer or USB accessory regardless of how long it was since the device was last authenticated. This means that those using GrayKey boxes no longer have that hour-long window.

Apple says that its motives behind such moves are not to simply prevent the use of GrayKey boxes, but at this point, it’s becoming pretty clear to everyone that this is the main driving force behind the arrival of USB Restricted Mode and, in particular, this new, tweaked version of the feature.