Anyone got any information on how the text rendering bug actually works (not just hand-waving it away as "oh it's UTF-8")?<p>I can see that the file alternates between segments of:<p>- Repetitions of the glyph "t̴́̍̒", which is a lowercase t with a combining tilde overlay, an acute accent, a vertical line above, and a turned comma above<p>- Random-looking ASCII characters with lots of apostrophes (spelled as &#39; in the HTML)<p>- Short sequences of spaces, non-breaking spaces, and zero-width joiners<p>- Occasional emoji<p>The "t̴́̍̒"s manage to slow down my terminal and glitch its rendering a bit. Is it that they're unexpectedly tall? But we've had zalgo-text for a while and it hasn't actually crashed devices.
Come to think of it, I believe I've heard of multiple "making the device render this text causes a crash" bugs for Apple devices, but never on any other platforms. Is this type of bug just that much more common on Apple devices, or are there plenty of other cases out there that I just don't know about?
Based on a web search, <a href="https://bogdanz.me/work/diddu.html" rel="nofollow">https://bogdanz.me/work/diddu.html</a> might be a working mirror of the proof of concept.<p>It appears to contain a 10MB long UTF-8 mess in both the og:title meta content and in a mailto: link.<p>I'd guess it's supposed to crash iOS apps by either posting that link if it displays links in a thumbnail element using og:title or otherwise by pasting the huge mailto link contained in the webpage, or perhaps only the e-mail address.
The linked blog assures people that this can't be used to access data. Once something is crashing an app/OS, can you really say that? I mean, can you be sure there's no one clever enough to capitalize on the underlying software error leading to this state?
Fixed in the latest beta: <a href="https://www.macrumors.com/2018/01/17/apple-seeds-ios-11-2-5-beta-6-to-developers/" rel="nofollow">https://www.macrumors.com/2018/01/17/apple-seeds-ios-11-2-5-...</a>
So a crashing bug in the text rendering framework is now worth an article in major publications?<p>I stumbled over two or three of them in the last couple of years while debugging crash reports sent in by customers.<p>Seems that text rendering is hard. Maybe fuzzing CoreText would be a worthwhile target to discover vulnerabilities?
There was an issue a few years ago where you could send a UTF-8 code to crash whatever app was currently open on an iPhone. I guess this might be the same issue but slightly different?
This again? It's eerily similar to <a href="https://m.huffpost.com/us/entry/7452324" rel="nofollow">https://m.huffpost.com/us/entry/7452324</a> (sorry for the mobile link). Only one other comment mentions the bug from 2015 that surprise, crashes the phone in the same way. It looks like this person just worked around the patch to cause it again.
I've noticed that iOS will only perform requests to links in iMessage if and only if the sender is in your contacts. If an unknown sender iMessages you a URL, iOS will <i>not</i> perform a request.
Considering that this text causes issues on other platforms than just Apple (with differing levels of severity), I would posit that it's unfair to characterize this as an "Apple bug".
Their lock screen crashing bug from iOS 11 that was fixed with 11.1 came back with 11.2 and I want to throw the thing out the window. Every time I hit the power button it crashes and have to type out the pin.