Chinese Censorship Run Amuck Crashes iPhones With Taiwan Flag Emoji

China has no love for Taiwan, and the former's censorship has led to strange issues for some iPhone users. If users have their region set to China and someone sends them the Taiwan flag emoji, a bug in iOS could cause the app to crash. That bug has the potential to allow a remote user to launch a denial of service attack on the message receiver by continually sending them the Taiwan flag emoji. The bug was discovered by security researcher Patrick Wardle.

Wardle says that the bug was first brought to his attention when a friend told him that iOS apps crashed when she typed the word "Taiwan" or received a message with the Taiwanese flag in it on a fully patched iPhone 7. In his debugging of the crash on the iPhone, he found that a function related to emoji processing was returning NULL causing the querying app to crash.

In his research, Wardle found that iOS strips out the Taiwanese flag emoji from received messages if the user has their region set to China. This is likely done at the request of China, a country that doesn’t recognize Taiwan as a country. The second image here shows a list of the flag emoji available in iOS with the Taiwan flag clearly seen in the USA region emoji list. In the Chinese Emoji list, the Taiwanese flag is missing.

Curiously, the friend with crashing apps who turned Wardle onto the bug had her region set to USA and was still seeing the error. The fix for her was reportedly to set the device to China region and then turn it back to USA region. Apple has patched this bug in iOS 11.4.1 that recently launched. This isn’t the first character that could crash iPhones via text, previously a flaw in iOS crashed devices when a single Indian language character was received.