A research team from Elcomsoft has discovered a new iPhone feature called USB Restricted Mode when going over the code for iOS 11.4, and it functions exactly as it sounds -- it deactivates any transfer of data over USB if the iPhone unit has not been unlocked for a period of a week. The USB data transfer will be reactivated when a user unlocks the device (by normal means), and even if the USB Restricted Mode is still on, the iPhone will still be capable of charging.
Whenever an Apple smartphone is plugged into another device or machine, some data is transmitted back and forth, especially in the process of detecting each other. Despite some layers of protection put in place, other machines still try to exploit this connection. The new USB Restricted Mode feature basically serves as a new added protective layer designed to ward off intruders who are willing to wait for a few days or weeks before pouncing. One can argue that the USB Restricted Mode on iPhone devices could also prevent law enforcement agencies from accessing an iPhone (like one that is sitting in evidence for some time now). If investigators find themselves in this kind of scenario, they better move in fast.
But as for casual consumers, it can prove useful. For those embarking on long business or vacation trips who inadvertently leave their iPhones behind, they can rest assured that after a week, their handsets will go on restricted mode automatically.
Some may remember that a little more than a couple of months ago, two companies have reportedly claimed that they can bypass the unlock security features of the iPhone X. One of them was United States based firm Grayshift, who had begun to distribute promotional materials for an unlocking tool called GrayKey. What this tool does basically is unlock an iPhone unit by guessing the passcode again and again.
The new USB Restricted Mode may well indeed be a response to GrayKey. The unlocking tool, after all, can only work by accessing the iPhone’s lightning port. Nobody knows for sure yet if the USB Restricted Mode will prove effective against GrayKey, but law enforcement agencies have shown relatively recently that they are open to the idea of acquiring the services of a third party provider (like GrayShift). In other words, if ever a locked iPhone unit gets investigated by the feds in the future, it is quite possible that they could take full advantage of what the GrayKey tool can offer.
