Apple Rolls out USB Restricted Mode Feature to Protect Devices

Apple has rolled out a new feature called USB Restricted Mode with the release of iOS 11.4.1 that can protect your devices against USB accessories that connect to the data port, making it difficult for attackers to break into iPhone or IPad without user’s permission.

Ankush Johar, director, Infosec Ventures, an organization that provides complete infrastructure security solutions for commercial and government clients of all sizes, said that in order to bypass this feature hacker will have to gain access to the device within one hour of it being locked. This obviously limits the capabilities of the attack. A thief might be able to attach such a USB accessory immediately after taking a mobile device but in case of a state-sponsored crack, it will become nearly impossible for cases like the San Bernardino shooter where gaining physical access of the device within an hour of it being locked is extremely improbable for authorities.

Although it’s not a critical vulnerability, crackers around the world are still trying to figure out a way to break into this prevention mechanism and it won't come as a surprise if they succeed too. It's a cat and mouse game. One will patch and another will crack again, Johar said.

How does the feature work?

If the iPhone or iPad has been locked for an hour or more the USB Restricted Mode automatically disables data connection capabilities of the Lightning port on your iPhone or iPad, thus limiting it to charging only.

The company, on its parts, claims that as soon as the USB Restricted Mode gets activated, there is no way left for breaking into an iPhone or iPad without the user's permission.

This particular feature promises to stop devices like GrayKey (which plugs into an iPhone and cracks the passcode within a few hours) from working successfully.

How can the hackers bypass USB Restricted Mode?

Various research works suggest that hackers can bypass USB Restricted Mode by directly connecting a USB accessory—such as Apple's $39 Lightning to USB 3 Camera adapter—to a targeted iOS device within 60 minutes after it was last unlocked would reset the 1-hour countdown.