Beware of the text message that crashes iPhones


Newly discovered iOS bug triggers wave of text messages that causes iDevice reboot.

According to people investigating the bug on reddit, the text causes iPhones running various versions of iOS to promptly crash. A flurry of Twitter users, angry that their devices fell victim to text messages, indicates that the bug is causing problems. Apple will almost certainly issue a fix. In the meantime, users can protect themselves against the nuisance text by going to system settings, navigating to Notifications>Messages>Show Previews, and turning it to off.

That change will prevent attacks that are currently circulating online, but it may not stop miscreants from finding new ways to crash people’s iDevices. According to the reddit thread, messages sent over WhatsApp may also trigger the crash. And depending on the way individual apps parse Unicode glyphs, other programs may do the same thing. The bug can also trip up OS X, although the attack requires a target to concatenate or paste a malicious file into the Mac terminal, according to a researcher who goes by the Twitter handle Hacker Fantastic.

Hacker Fantastic has tweeted a variety of other interesting technical details. The bug, he reported, resides in a part of the operating system that processes Unicode glyphs and causes a string to be written to a particular memory location. The bug is tied to the way banner notifications process Unicode, reddit reader sickestdancer98 reported. The banner is unable to display the text and eventually crashes the entire OS.

While the bug is rightfully regarded primarily as a nuisance, denial-of-service vulnerabilities can often be the result of serious flaws that, with more work, can be exploited to perform code-execution attacks. And even when more malicious exploits aren’t possible, DoS holes can sometimes present opportunities for extortionists or people looking to disrupt large events—for instance people at a conference. Expect Apple to release a patch in the coming week or so.