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A new CSS-based web attack will crash and restart your iPhone

techcrunch.com

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Re: A new CSS-based web attack will crash and restart your iPhone

#85

Post by MBCook »

amaccuish wrote: post #75
KenanSulayman wrote: post #40

I tried it on my iPhone X and it triggers a kernel panic (agxk_mmu.cpp) when trying to allocate memory for WebKit. It seems it exhausts the memory so fast that it triggers an assertion error somewhere? Screenshot: https://i.imgur.com/6tDr44q.png Full serial console log of the device: https://gist.githubusercontent.com/KenanSulayman/867cc399e97...

Does iOS not enforce reasonable memory limits on apps to prevent a panic?

It does. Your app will get killed. The OS will be fine.

My understanding is this bug uses up GPU memory/contexts, not normal system RAM, and that’s why it becomes an issue.

Re: A new CSS-based web attack will crash and restart your iPhone

#86

Post by nothrabannosir »

runeks wrote: post #69

Can anyone confirm if this is a denial-of-service attack (through memory exhaustion)? I’m no security researcher but, as I understand, it shouldn’t be exploitable if this is the case.

DoS of safari or the kernel? It's a kernel panic, which is not a safari dos; no user space app should be allowed to crash the kernel. Memory exhaustion should just trigger an OOM kill at worst.

Re: A new CSS-based web attack will crash and restart your iPhone

#87

Post by signal11 »

matkins wrote: post #67
Crontab wrote: post #60

Earlier quoted context omitted.

"Seems like on restart Safari wants to revisit previously opened pages" I've always found that behavior annoying. If I want to revisit the last page, I can find it in history.

I'm sure you're in the absolute minority. Most people want all apps, including the browser, to stay the way they were when they closed them, even after a reboot

But that’s why you need a “safe start mode” where you can start the app with a clean slate. Several Microsoft Office apps do this now. Given iOS’s repeated “crash loop” issues you’d think they’d have learnt by now.

Re: A new CSS-based web attack will crash and restart your iPhone

#88

Post by watermans »

qrbLPHiKpiux wrote: post #59
novaRom wrote: post #51

I've stopped accepting iOS/OSX seriously after those iCloud celebs leaks and especially after 'empty string' root prompt bug. How anyone can still trust this black box concept.

Weren't those phishing compromises?

They were. OP seems to have bought into the fake story that someone legitimately hacked iCloud and only made it out with photographs.

Re: A new CSS-based web attack will crash and restart your iPhone

#89

Post by gsnedders »

amaccuish wrote: post #74

Is this due to memory exhaustion? If so, does Safari not have limits applied that cause it to be killed for running into OOM?

> If so, does Safari not have limits applied that cause it to be killed for running into OOM?

It does. The memory allocation that causes the crash doesn't come from Safari, though: it's a memory allocation in the kernel (likely somewhere graphics related), and that counts towards XNU's memory consumption and not Safari's.

Re: A new CSS-based web attack will crash and restart your iPhone

#90

Post by bdcravens »

matkins wrote: post #67
Crontab wrote: post #60

Earlier quoted context omitted.

"Seems like on restart Safari wants to revisit previously opened pages" I've always found that behavior annoying. If I want to revisit the last page, I can find it in history.

I'm sure you're in the absolute minority. Most people want all apps, including the browser, to stay the way they were when they closed them, even after a reboot

That always bothers me. What if a page was (dumbly) in a state that makes a change I don't want?
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