Wednesday, December 11th 2019

New "Plundervolt" Intel CPU Vulnerability Exploits vCore to Fault SGX and Steal Protected Data
A group of cybersecurity researchers have discovered a new security vulnerability affecting Intel processors, which they've craftily named "Plundervolt," a portmanteau of the words "plunder" and "undervolt." Chronicled under CVE-2019-11157, it was first reported to Intel in June 2019 under its security bug-bounty programme, so it could secretly develop a mitigation. With the 6-month NDA lapsing, the researchers released their findings to the public. Plundervolt is described by researchers as a way to compromise SGX (software guard extensions) protected memory by undervolting the processor when executing protected computations, to a level where SGX memory-encryption no longer protects data. The researchers have also published proof-of-concept code.
Plundervolt is different from "Rowhammer," in that it flips bits inside the processor, before they're written to the memory, so SGX doesn't protect them. Rowhammer doesn't work with SGX-protected memory. Plundervolt requires root privileges as software that let you tweak vCore require ring-0 access. You don't need direct physical access to the target machine, as tweaking software can also be remotely run. Intel put out security advisory SA-00298 and is working with motherboard vendors and OEMs to release BIOS updates that pack a new microcode with a mitigation against this vulnerability. The research paper can be read here.
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Plundervolt
Plundervolt is different from "Rowhammer," in that it flips bits inside the processor, before they're written to the memory, so SGX doesn't protect them. Rowhammer doesn't work with SGX-protected memory. Plundervolt requires root privileges as software that let you tweak vCore require ring-0 access. You don't need direct physical access to the target machine, as tweaking software can also be remotely run. Intel put out security advisory SA-00298 and is working with motherboard vendors and OEMs to release BIOS updates that pack a new microcode with a mitigation against this vulnerability. The research paper can be read here.
74 Comments on New "Plundervolt" Intel CPU Vulnerability Exploits vCore to Fault SGX and Steal Protected Data
... Or just that the general public is being made more aware of it and it was always risky.
In all seriousness, NO ONE engineers vulnerabilities into their technology because everyone knows hackers/researchers have and will find them.
So switching off SMT is a mitigation and it does reduce performance.
The point is, these vulnerabilities are being fixed by hardware changes. No, existing CPUs will not be fixed for obvious reasons but newer revisions of CPUs have (some of the the) issues fixed in hardware. On these CPUs with fixes, mitigations are no longer needed and there is no performance penalty compared to pre-mitigation state. Changes in hardware are mitigations for some of the overarching issues like Spectre (1/2) but the way other issues are addressed seem to be straight-up fixes. Phoronix' mitigation articles for Cascade Lake or newer should be a reputable enough source? Keep an eye on software mitigations that are enabled or disabled in these.
Just look at the single threaded performance. 630. its a 5400 MHz i9-9900K w/o HT. By far would be the best gaming chip. Intel wasn't lying when they said their CPUs are better than AMD's for gaming *when overclocked*, and here is why. For comparison, a 4300 MHz 3600X only hits 522 on single threaded. So yes, Intel's CPUs are still the fastest for gaming. And that's it. Everything else, AMD wins. More cores, more efficiency, more IPC (not enough to make up for an overclocked Intel chip unfortunately), cheaper *decent* motherboards, you name it, AMD is better. But for gaming specifically, Intel is faster. Yes more expensive, but in competitive esports, it can make all the difference.
This is as correct as your statement that the fixes don't impact the performance.
Ice Lake, the 10nm models of 10th gen are a bit of unknown. These do not seem to have the same vulnerabilities but the information on these is not very easily found. For example the latest Zombieload V2 list of affected CPUs includes Comet Lake 10th gen but not Ice Lake 10th gen. According to what mitigations are enabled by OSs (based on various screenshots and details from the net) as well as Phoronix' mitigation testing articles Ice Lakes do not seem to have most of the speculative execution vulnerabilities.
Again, performance penalty comes largely or entirely due to how mitigations work - these are done is software or firmware to avoid certain vulnerable microarchitectural states as much as possible. When this is ensured to not happen with changes in hardware, software mitigations (and their performance penalty) will not be applied. So far, there does not appear to be a discernible performance difference from fixed vulnerabilities when the fix is in hardware.
When we talk about performance and leave other aspects aside it is very much in Intel's interests to fix as many of these issues as quickly as possible. This does appear to be exactly what they are doing with caveat that the timeframe in question is a year or more. A vulnerability is reported, usually put under embargo for 6 months, then it is published along with some type of mitigations (software, firmware) and next model or revision of CPUs will include a fix for the vulnerability in hardware. In broad strokes this is how all of the issues since Spectre/Meltdown have been handled.
As for why companies do still buy Intel, it's not only about market and agreements, it's the complete package. Intel offers the entire platform since the centrino days and have been unmatched since opteron fell behind, it's not like companies will switch to a different platform in the first vulnerability found, things cost money. Reading comments here is like when someone laughs when they find out lots of goverment or big company equipment run on windows xp, like things like hardening or exclusive special contracts with microsoft to keep patching vulnerabilities doesn't exist. Come on guys.
10 years ago that might be as dumb as you described, but today's tech is not the same.
I wouldn't be surprised if everyone on these forums has been affected by at least one data breach (haveibeenpwned.com). Yes, some of those breaches will be careless handing of data, but there are plenty of data breaches where the data holder has done everything right but been hit by an unpatched exploit.
These exploits need to be patched. They will be patched, eventually. There will almost certainly be a small performance penalty and on its own the impact will be negligible, but there have been so many of these patches for the ancient Intel architecture that they're cumulatively a significant performance penalty.