05-15-2019, 07:44 AM
https://www.techpowerup.com/255508/yet-a...h-gen-cpus
Quote:The issue at hand here, defined by Intel's pretty tame MDS, is that like other side-channel attacks, exploits may allow hackers to obtain information that was otherwise deemed secure, had it not been run through the CPU's speculative execution processes. While Meltdown read sensitive information that was being stored in memory due to the speculative execution functions on Intel's CPUs, MDS attacks read the data on the CPU's various buffers - between threads, along the way to the CPU's cache, and others. The researchers say that this flaw can be used to siphon data from the CPU at a rate that can approach real-time, and can be used to selectively pull what information is deemed important: whether passwords or what websites the user is visiting at the moment of the attack, it's all fair game.
Intel says that significant software changes will be needed to harden systems against this exploit, not only from themselves, but from operating system designers and third party app creators. One of the proposed solutions is that every time a processor would switch from one third-party app to another, from a Windows process to a third-party app, or even from less trusted Windows processes to more trusted ones, the buffers have to be cleared or overwritten. This means a whole new cycle of data gathering and writing every time you call up a different process - and you bet that carries a performance penalty, which Intel is putting at a "minimal" up to 9%.
Intel in its white paper detailing the vulnerability admitted that disbaling HT might be warranted as a protection against MDS attacks - and you can imagine how much the company must have loathed to publish such a thing. Intel's HT has been heavily hit by the repeated speculative executon flaws found on Intel processors, with mititgations usually costing some sort of performance on Intel's concurrent processing technology. Intel says its engineers discovered the MDS vulnerabilities last year, and that it has now released fixes for the flaw in both hardware and software. Although obvisously, the software fixes will have to be deployed either on microcode updates or will have to be implemented by every operating system, virtualization vendor, and other software makers.
Intel also said that its 8th and 9th generation processors already include the hardware mitigations that defeat the exploitaition of MDS, but previous architectures back to Nehalem are vulnerable. But why play it on expectations: you can take a test that has been published by the researchers right here.