CacheOut: Leaking Data on Intel CPUs via Cache Evictions
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CacheOut: Leaking Data on Intel CPUs via Cache Evictions
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Re: CacheOut: Leaking Data on Intel CPUs via Cache Evictions
#2Did AMD design their processors with these side channel attacks in mind, or is it a matter of where the security research is focused?
Re: CacheOut: Leaking Data on Intel CPUs via Cache Evictions
#3Is this coordinated with OS providers? It only mentioned that Intel released microcode.
Re: CacheOut: Leaking Data on Intel CPUs via Cache Evictions
#4Did AMD design their processors with these side channel attacks in mind, or is it a matter of where the security research is focused?
> AMD is not affected by CacheOut, as AMD does not offer any feature akin to Intel TSX on their current offering of CPUs.
It seems to be down to the notoriously buggy TSX (hardware transactional memory) in Intel CPUs.
Re: CacheOut: Leaking Data on Intel CPUs via Cache Evictions
#5Did AMD design their processors with these side channel attacks in mind, or is it a matter of where the security research is focused?
Amd still has almost no server marketshare. This attack specifically leverages tsx, which is an Intel set of transactional extensions to the cpu microcode. Intel has since published microcode updates to enable you to disable tsx.
Re: CacheOut: Leaking Data on Intel CPUs via Cache Evictions
#6Did AMD design their processors with these side channel attacks in mind, or is it a matter of where the security research is focused?
In this case AMD just doesn't support TSX instructions. For previous vulnerabilities with Meltdown I'd guess that AMD just didn't feel they had the engineering resources to do after the fact validation of memory access permissions without architecturally leaking data in some weird corner case. But then along comes Meltdown and it turns out that non-architectural leaks are a thing that can happen and if you try to do after the fact validation you can't prevent them.
Re: CacheOut: Leaking Data on Intel CPUs via Cache Evictions
#7rgy g
Re: CacheOut: Leaking Data on Intel CPUs via Cache Evictions
#8I mean, you gotta appeciate their efforts to make something so technical approachable by the general population, including gems like this in their Q&A: :-D:
What is an operating system?
An operating system (OS) is system software responsible for managing your computer hardware by abstracting it through a common interface, which can be used by the software running on top of it. Furthermore, the operating system decides how this hardware is shared by your software, and as such has access to all the data stored in your computer's memory. Thus, it is essential to isolate the operating system from the other programs running on the machine.
Re: CacheOut: Leaking Data on Intel CPUs via Cache Evictions
#9Did AMD design their processors with these side channel attacks in mind, or is it a matter of where the security research is focused?
Mostly, it seems to be a difference in design philosphy - AMD processors prevent speculative reads of data that shouldn't be accessible almost everywhere, whereas Intel ones allow them pretty much everywhere. This particular attack requires TSX which AMD processors don't have, but I don't think it'd work on AMD processors anyway because they're not missing the security check that Intel ones are. If I remember rightly, there were other now-mitigated exploits for this line fill buffer leak that didn't require TSX.
(The one exception is also interesting. AMD processors allow speculative reads past the end of x86 segments and past BOUND instructions, which of course no-one uses these days. This suggests there may have been a deliberate decision to block them in the more important cases.)
Re: CacheOut: Leaking Data on Intel CPUs via Cache Evictions
#10Did AMD design their processors with these side channel attacks in mind, or is it a matter of where the security research is focused?
It is specific to Intel TSX, which should already be disabled due to earlier published MDS vulnerabilities in the same space.