A malicious video link has been circulating that when played on Safari on an iOS device can cause the device to crash.
Playing the MP4 video in question through Safari appears to have no effect at first, but gradually the operating system slows down before it freezes completely, after which only a hard reset will bring the device back to life. YouTube channel EverythingApplePro has posted a demonstration (i.e. not the original video) showing the exploit in action.
The exploit seems to work on devices running iOS versions as old as iOS 5. Even on the latest iOS 10.2 beta 3, the exploit works and leads the devices to show a spinning wheel indefinitely. If you end up opening the video, the only way to fix your iOS device is to hard reset it. On the iPhone 6s and older devices, you will have to press the power and Home buttons for a few seconds, while on the iPhone 7, you will have to hold down the power and volume button.
The video likely takes advantage of some memory leak in iOS to be able to send iPhones and iPad into a boot loop. Now that the exploit is being reported by the mainstream press, it is likely that Apple will fix the issue in the next beta or final release of iOS 10.2.
This kind of prank isn’t new. Three years ago, a text exploit made the rounds that caused both Mac and iOS devices to crash.