A video has been found to freeze (a.k.a. cause a denial of service attack) on various models of Apple mobile devices. Within minutes, the iPhone becomes unusable; the only way to recover is a hard reboot by holding down the Home and Power buttons simultaneously for a couple of seconds. At this time of writing, it is unclear what is causing Apple devices to freeze. One possible theory was a memory issue with one of the MP4 codecs.”]
Source: https://blog.malwarebytes.com/cybercrime/2016/11/video-found-freezing-apple-devices/