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Unpatchable vulnerability in Apple chip leaks secret encryption keys (arstechnica.com)

submitted 5 months ago by mox@lemmy.sdf.org to c/technology@lemmy.world

6 comments fedilink hide all child comments

The attack has been dubbed GoFetch: https://gofetch.fail/

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[–] Spedwell@lemmy.world 0 points 5 months ago* (last edited 5 months ago) (2 children)

Wow, what a dishearteningly predictable attack.

I have studied computer architecture and hardware security at the graduate level—though I am far from an expert. That said, any student in the classroom could have laid out the theoretical weaknesses in a "data memory-dependent prefetcher".

My gut says (based on my own experience having a conversation like this) the engineers knew there was a "information leak" but management did not take it seriously. It's hard to convince someone without a cryptographic background why you need to {redesign/add a workaround/use a lower performance design} because of "leaks". If you can't demonstrate an attack they will assume the issue isn't exploitable.

[–] Killing_Spark@feddit.de 0 points 5 months ago* (last edited 5 months ago)

So the attack is (very basically, if I understand correctly)

Setup:

I control at least one process on the machine I am targeting another process on
I can send data to the target process and the process will decrypt that

Attack:

I send data that in some intermediate state of decryption will look like a pointer
This "pointer" contains some information about the secret key I am trying to steal
The prefetcher does it's thing loading the data "pointed to" in the cache
I can observe via a cache side channel what the prefetcher did, giving me this "pointer" containing information about the secret key
Repeat until I have gathered enough information about the secret key

Is this somewhat correct? Those speculative execution vulnerabilities always make my brain hurt a little

[–] lightnegative@lemmy.world 0 points 5 months ago (1 children)

If you can't demonstrate an attack they will assume the issue isn't exploitable.

Absolutely. Theory doesn't always equal reality. The security guys submitting CVE's to pad their resumes should absolutely be required to submit a working exploit. If they can't then they're just making needless noise

[–] Killing_Spark@feddit.de 0 points 5 months ago

There are definitely bullshit cves out there but I don't think that's a good general rule. Especially in this context where it's literally unpatchable at the root of the problem.