iOS bug lets anyone crash your iPhone by sending a single character
The message in question has to contain a single character from the Indian Telugu language (not included here for obvious reasons). When the message is opened on an iPhone running iOS 11.2.5, the iPhone’s native Messages app and certain third-party app including WhatsApp and Facebook Messenger will crash. In some cases, the iPhone will simply revert to its login screen and require you to enter your PIN again.
Apparently the only way to fix it is to delete the message thread, which you’ll presumably have to do from a Mac app or desktop web browser, depending on the service. If that’s not available to you, you might be able to delete the thread when you receive a new message on it.
This is the latest in the fairly long line of many similar bugs which allow attackers to crash an iOS device by sending a simple text message. Last month, a bug dubbed ChaiOS let attackers freeze/crash iPhones by sending a text message containing a specific link; Apple fixed that one within a week. And last year a bug was discovered that crashes an iPhone with a message containing a combination of emoji.
We’ve tried to test the bug with Messages on an iPhone running iOS 11.2.2 and 11.2.5 and did not achieve the same result (the iPhone was fine). We’ve contacted Apple regarding this issue and will update this article when we hear from them.