‘Black Dot’ Unicode Text Handling Bug Crashes iOS 11.3 and iOS 11.4

A new Unicode “Black Dot” Text bug is began spreading across iOS devices on Wednesday, after a video (seen below) was published by EverythingApplePro which demonstrates the bug.

9to5Mac:

The iOS version of this bug is a bit different in its mechanics, but neither variants actually rely on the visible black dot character to cause the freezes and crashes.

The secret is that the strings contain thousands of hidden invisible Unicode characters, which churns through CPU cycles as the system attempts to process them. If this specially crafted text is sent through Messages, it will result in repeated crashes when the recipient tries to read it. 

9to5Mac’s Benjamin Mayo reports iOS isn’t the only Apple platform affected, as when the link to the text was copied on his Mac, it “caused my Mac’s memory usage to spiral out of control, creating a 30 gigabyte swap file in the process.” It is possible the bug could also affect watchOS and tvOS devices.

The theory about the flaw is that the amount of invisible characters in the string causes the device’s text processing engine to go into a loop when processing the string, ultimately locking up the app and OS. The bug works on iOS 11.3 and the current iOS 11.4 beta seed.

If this happens to you, first get new friends, but there is a fix (via CNet):

• If the bug crashes your iMessages, force close the iMessage app
• Then 3D Touch the iMessage app from the home screen, and select “New Message”
• Hit “cancel” on the New Message screen, and that’ll take you back to your list of iMessage convos
• From there you can delete the message with the bug

If your phone doesn’t have 3D Touch, you can still fix it. (Via MacRumors):

• Force closeiMessage
• Bring up Siri and ask it to “Send a reply to… [whoever sent you the bug]”
• Keep sending replies through Siri until the bug is off screen in the iMessage conversation
• Open iMessage and hit back so you get to the conversation list
• From the conversation list, you can delete the thread with the bug

We expect Apple to address the bug with an update shortly. We’ll keep you posted.