Fact Check

iPhone 'Effective', 'Power' iMessage Glitch

Published May 27, 2015

Claim: Receipt of a specific text message including the words "effective", "power", and a string of characters in Arabic and will immediately cause iPhones to shut down due to a glitch or bug.


Comment: iPhone Users Beware: If You Get This Text Message, Your Phone Will Likely Turn Off Immediately

Origins:   On 22 May 2015, a Reddit user posted a thread to the site's subreddit r/OutOfTheLoop titled "What is this new iPhone thing where sending a certain message shuts down your phone?" which explained that:

Someone with an android phone showed me the message, it was a few characters long and looked like Arabic or Unicode characters.

On the same day, a user posted similar message to Reddit's r/technology forum that included an example of a phone-shutting-down text slightly longer than the later, more popular version:

How can you compare Humans with rats? Of course I can't compare humans with rats. But they have almost the same body structure, if most things don't work for humans even though it works for rats, how would so many scientists choose rats to do a trial? Jessica Samakow whom's a managing editor on huff post voices had a poll of corpora punishment which says 81 percent of 1,000 adults think spanking their children should be legal because the deterrence of it is the most effective. Power لُلُصّبُلُلصّبُررً ॣ ॣh ॣ ॣ 冗

When sent in whole, it purely restarts the person who is receiving the message's phone. When only the text after the word Power is sent, the messages app refuses to re-open whether the phone is restarted or anything. I wanted to see if anyone has seen this and/or has a fix for it.

At some point between the spate of threads posted to Reddit on 21 May 2015 and a spike in interest in the iPhone text on 26 May 2015, that phone-clobbering message was shortened to "effective. Power ... " and the string of Arabic characters.

Popular Apple-centric site MacRumors tweeted about the text message and its rumored effects:

On 26 May 2015, a Reddit user speculated that the purported glitch was caused by a combination of disparate characters:

Cracked it.

It only works when the message has to be abbreviated with '...'. This is usually on the lock screen and main menu of Messages.app.

The words effective and power can be anything as long as they're on two different lines, which forces the Arabic text farther down the message where some of the letters will be replaced with '...'

The crash happens when the first dot replaces part of one of the Arabic characters (they require more than one byte to store) Normally there are safety checks to make sure half characters aren't stored, but this replacement bypasses those checks for whatever reason.

The precise cause of the glitch was later explained in detail by the Register:

A 75-byte sequence of unicode characters triggers the glitch, and can be smuggled into text messages, causing iThings to crash if they appear in the victim's notification screen. Texting the data to your pals will force their devices to reboot if they try to open it from the notification panel.

The string-of-death crashes applications that use Apple's CoreText library. OS X is vulnerable, too, so sticking the killer sequence in your server's /etc/motd file will crash Terminal when a Mac user logs in, for example.

The flaw was spotted by a Redditor who received the message, which caused their smartphone to crash and reboot to recover. The attack has been replicated on other iOS devices such as Apple's smartwatch.

The problem isn’t with the Arabic characters themselves, but in how the unicode representing them is processed by CoreText, which is a library of software routines to help apps display text on screens.

The bug causes CoreText to access memory that is invalid, which forces the operating system to kill off the currently running program: which could be your text message app, your terminal, or in the case of the notification screen, a core part of the OS.

On 29 May 2015, Apple published a temporary workaround for the problem until it is addressed in a software update:

If Messages quits unexpectedly after you get a text with a specific string of characters

Apple is aware of an iMessage issue caused by a specific series of unicode characters and we will make a fix available in a software update. Until the update is available, you can use these steps to re-open the Messages app:

Ask Siri to "read unread messages." Use Siri to reply to the malicious message. After you reply, you'll be able to open Messages again. If the issue continues, tap and hold the malicious message, tap More, and delete the message from the thread.

Kim LaCapria is a former writer for Snopes.

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