A bug in Apple’s iOS means that anyone can crash an iPhone by simply sending it a certain string of characters in a message. The bug, discovered by several Reddit users, means that when the message is received it instantly crashes the iPhone and causes it to reboot, as long as the recipient is not viewing their message history at the time. The attack appears to be caused by a glitch in the way Apple’s iOS mobile operating system, which runs on the iPhone, iPad and iPod touch, renders Arabic text.