Apple published a temporary workaround for the iOS bug that allows an iMessage or text with the select set of characters to reboot/respring iPhones and crash the Messages app.
Apple has said that it will release a software update to fix the bug that is also called “Effective Power” due to the use of the words in the malicious string.
Jailbreakers, if you don’t want to wait then install the jailbreak tweak called IneffectivePower developed by Karen aka angelXwind, which prevents your Messages app from crashing and also rebooting your iPhone.
IneffectivePower is a tweak I wrote that stops the infamous “Effective Power” text string from crashing CoreText on a system-wide level. This means it should work in every app.
There are other jailbreak tweaks like GlyphPatch that fix the issue, but Karen explains why IneffectivePower is a better option.
IneffectivePower works on a system-wide level, because its modifications are being applied at the CoreText level as opposed to being injected into SpringBoard.
All of the other tweaks, except for one (“AntiEffective”), only inject into SpringBoard and MobileSMS.
As far as AntiEffective goes, it doesn’t completely fix the issue, and will still crash in certain apps (Twitter, Facebook Messenger, AMRC, etc.)
MohammadAG, Hacker and developer, who had also developed a tweak to fix the issue called Unicode Suppressor, has also recommended using Ineffective Power since it fixes the CoreText bug.
We’ve tested it, and a text with the select set of Arabic/Unicode characters did not reboot/respring our jailbroken iPhone or crash the Messages app after installing the tweak.
IneffectivePower is available for free. Add the http://cydia.angelxwind.net/ repo to install the tweak. It will work even after getting the text with the Arabic/Unicode characters.
It is one of the great things about the jailbreak community. They can fix such issues even before Apple, and it is not the first time they’ve done it. It is also great for jailbreakers, as you don’t need to upgrade to iOS 8.4 (or the next software update) to fix the issue, and lose the jailbreak.
Let us know how it goes.
Thanks Erick121 for the tip!