In addition to bug fixes and performance enhancements, Apple has introduced an important security feature with the release of iOS 11.4.1. The new setting will block USB access to iOS devices after an hour of inactivity, making it difficult for the police to use utilize hacking tools.
Some couple of months ago, it was a reported that law enforcement officials were using a technology to crack locked iPhones. According to the report, these officials connects to an iOS device via the USB port and then exploits Apple’s software. That being said, this new feature in iOS 11.4.1 will disable USB access when a phone has been locked for an hour or more.
According to Apple,
We’re constantly strengthening the security protections in every Apple product to help customers defend against hackers, identity thieves, and intrusions into their personal data. We have the greatest respect for law enforcement, and we don’t design our security improvements to frustrate their efforts to do their jobs.
By default, the USB Restricted Mode toggle is switched to off, which is what Apple wants. So, if you do decide to give USB accessories access to your iPhone after an hour of being locked, you can find the setting by going into Settings > Face ID or Touch ID & Passcode and scroll down.