Unpatchable vulnerability in Apple chip leaks secret encryption keys
Unpatchable vulnerability in Apple chip leaks secret encryption keys
Fixing newly discovered side channel will likely take a major toll on performance.
The attack has been dubbed GoFetch: https://gofetch.fail/
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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.
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
The more probable answer is that the NSA asked for the backdoor to be left in. They do all the time, it's public knowledge at this point. AMD and Intel chips have the requisite backdoors by design, and so does Apple. The Chinese and Russian designed chips using the same architecture models, do not. Hmmmm... They have other backdoors of course.
It's all about security theatre for the public but decrypted data for large organizational consumption.
I don't believe that explanation is more probable. If the NSA had the power to compell Apple to place a backdoor in their chip, it would probably be a proper backdoor. It wouldn't be a side channel in the cache that is exploitable only in specific conditions.
The exploit page mentions that the Intel DMP is robust because it is more selective. So this is likely just a simple design error of making the system a little too trigger-happy.
They do have the power and they do compel US companies to do exactly this. When discovered publicly they usually limit it to the first level of the "vulnerability" until more is discovered later.
It is not conjecture, there is leaked documents that prove it. And anyone who works in semiconductor design (cough cough) is very much aware.
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
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.