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ZombieLoad: Cross Privilege-Boundary Data Leakage on Intel CPUs
181–190 of 337 posts
Re: ZombieLoad: Cross Privilege-Boundary Data Leakage on Intel CPUs
#182So I'd love to post an Ask HN: Which AMD Laptops would you recommend for work, alternatives to Thinkpads? I've noticed some Thinkpads with AMD CPUs but I feel like I'm on virgin ground when it comes to AMD and their integrated GPU offerings.
I've just received in some Thinkpad E485's which have the Ryzen 2500U CPU. They seem pretty nice, with a 1080p screen that's non-glare. The documentation says they support Redhat Enterprise Linux and Ubuntu. So far they seem nice. I was thinking of trying PopOS on it and see how it runs.
Re: ZombieLoad: Cross Privilege-Boundary Data Leakage on Intel CPUs
#183Sorry for being naive. Are these kind of CPU Securities vulnerabilities new? Why it is in the past 20 years we have had close to zero in the news ( At least I wasn't aware of any ) and ever since Spectre and Meltdown we have something new like every few months. And as far as I am aware they are mostly Intel CPU only. Why? And Why not AMD? Something in the Intel design process went wrong? And yet all the Cloud Vendor…
> Why it is in the past 20 years we have had close to zero in the news ( At least I wasn't aware of any ) and ever since Spectre and Meltdown we have something new like every few months.
It's a new vulnerability class. Prior to Spectre, nobody thought that code which didn't execute (and couldn't execute) could affect architectural state in an observable way. It's hard to overstate how bizarre the vulnerabilities from the Spectre family are from a software point of view: it's leaking data from code that not only didn't execute yet, but also can never execute, and in some cases doesn't even exist! It's like receiving a packet your future self sent to the past, except that your future self had been dead for two years when he sent the packet, and for some reason he's actually a parrot.
Once a new vulnerability class is discovered, researchers will start looking for new bugs in and around that class. Which is why we have seen lately so many issues disclosed around speculative execution and data leaked through shared microarchitectural state.
Re: ZombieLoad: Cross Privilege-Boundary Data Leakage on Intel CPUs
#184People should realize that ancient Chinese were onto something when they told that all phenomena shall evolve only so much before they tip over the peak of maximum development and inevitably rumble downhill into overdevelopment.
P.S. Wow, hit a soft spot. Flagging this for what? For being unloyal to the ideology of everlasting growth? Try again as much as you can.
Re: ZombieLoad: Cross Privilege-Boundary Data Leakage on Intel CPUs
#185Apparently Intel attempted to play down the issue by trying to award the researchers with the 40,000 dollar tier reward and a separate 80,000 dollar reward as a "gift" (which the researchers kindly denied) instead of the maximum 100,000 reward for finding a critical vulnerability. Intel was also planning to wait for at least another 6 months before bringing this to light if it wasn't for the researchers threatening t…
> Intel was also planning to wait for at least another 6 months before bringing this to light Of course, until the legally agreed date when they can dump shares so there’s no obvious proof that it’s insider trading. Isn’t that what (then) Intel CEO Brian Krzanich did after Meltdown/Spectre?
Not sure why down voted, this sounds like the most logical reason
Re: ZombieLoad: Cross Privilege-Boundary Data Leakage on Intel CPUs
#186Earlier quoted context omitted.
Spectre variant 2 was a little more interesting in that it can trick the processor into speculative execution of something that's not a valid execution path for the victim context (by confusing it about the target of an indirect branch), but it still relies on the speculative execution happening in a context that is meant to have access to the targetted data. It's sort of halfway between this and the other Spectre va…
> All three of these latest vulnerabilities are like Meltdown and L1TF in that they just allow speculative execution to completely ignore hardware-level access protections and read data from a completely different process Not really. These attacks are completely different from Meltdown and L1TF in that they don't involve reading from memory at all. They involve hidden processor state that contains values that were re…
The "hidden processor state" is the memory contents belonging to other processes, stored as part of the CPU's memory access machinery. Every single one of these vulnerabilities involves Intel speculatively filling memory read requests from one process with data from another process without doing access checks first, and it turns out they do this all over the place: they do it from L1 cache, they do it if there's an L1 cache miss, they do it when the actual desired memory is uncacheable, they do it with store-to-load forwarding... almost every conceivable method of fulfilling a memory read on modern Intel CPUs is happy to speculatively leak secret data from other processes that shouldn't be accessable. More interestingly, AMD don't seem to do this anywhere that anyone's been able to find. (Well, technically that's not quite true... there's a speculative bypass of x86 segment limits on AMD which no-one cares about because no-one uses those anyway.)
Re: ZombieLoad: Cross Privilege-Boundary Data Leakage on Intel CPUs
#187People should realize that ancient Chinese were onto something when they told that all phenomena shall evolve only so much before they tip over the peak of maximum development and inevitably rumble downhill into overdevelopment. P.S. Wow, hit a soft spot. Flagging this for what? For being unloyal to the ideology of everlasting growth? Try again as much as you can.
Downvoted for the frothy edit. Chill out there ya toughy. Someone clearly hit a soft spot on you.
Re: ZombieLoad: Cross Privilege-Boundary Data Leakage on Intel CPUs
#188What is the recommended course of action? Stop buying Intel products, and devices which contain them? What about devices with older processors? I'm still running a Sandy Bridge rig and it works fine, except for the side channel vulnerablities. It's probably not going to be patched. I also have a cheaper computer with a Skylake processor, which is newer yet still vulnerable! It's only a matter of time until something…
The stream of critical CPU vulnerabilities starting with Spectre/Meltdown last year are related to speculative execution , not just Intel. (AMD and ARM CPUs are also vulnerable to Spectre, for example.) Intel CPUs are sometimes vulnerable to additional attacks because they speculate in more scenarios than other designs. But fundamentally, as long as multiple different trust domains are sharing one CPU that speculates…
> The safest bet now for the best security is probably to stick to in-order CPUs
out-of-order execution != speculative execution.
It is possible to have OoO without speculative execution. On the other hand they do tend to come as a pair since they both utilise multiple execution units, for instance the Intel Pentium in 1993 was the first x86 to have OoO or branch prediction (486 and those before were scalar CPUs).
Re: ZombieLoad: Cross Privilege-Boundary Data Leakage on Intel CPUs
#189Earlier quoted context omitted.
> Intel was also planning to wait for at least another 6 months before bringing this to light Of course, until the legally agreed date when they can dump shares so there’s no obvious proof that it’s insider trading. Isn’t that what (then) Intel CEO Brian Krzanich did after Meltdown/Spectre?
Not sure why down voted, this sounds like the most logical reason
Because they’d eventually have to disclose when the vulnerability was discovered and that’d be extremely obvious what they’re doing?
Re: ZombieLoad: Cross Privilege-Boundary Data Leakage on Intel CPUs
#190Earlier quoted context omitted.
If ARM and AMD CPUs are not affected, then speculative execution in general is not the issue.
But they are, ARM to both a Meltdown variant and Spectre, as well IBM's POWER and mainframe chips, and AMD to Spectre.
They are not for all kind of attacks.
E.g. this new one can only be reproduced on Intel, not on AMD and ARM.
If you want to ban speculative execution for everything, you need to make the case that it's a fundamental issue and not an implementation specific issue.
Right now, that's not the case for many of these vulnerabilities.