AMD is warning about a high-severity CPU vulnerability named SinkClose that impacts multiple generations of its EPYC, Ryzen, and Threadripper processors. The vulnerability allows attackers with Kernel-level (Ring 0) privileges to gain Ring -2 privileges and install malware that becomes nearly undetectable.
Tracked as CVE-2023-31315 and rated of high severity (CVSS score: 7.5), the flaw was discovered by IOActive Enrique Nissim and Krzysztof Okupski, who named privilege elevation attack ‘Sinkclose.’
Full details about the attack will be presented by the researchers at tomorrow in a DefCon talk titled “AMD Sinkclose: Universal Ring-2 Privilege Escalation.”
They’re issuing a fix for the 5000 series but not the 3000 series. As a 3000 series owner and with Intel cumming in customer’s eyes my next computer will be RISC-V Death to x86.
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AGESA update applied via BIOS update. Effectively just a microcode patch. Pretty common, and since we’re seeing Epyc CPUs from the same generation as Ryzen 3000/Zen 2 being patched, I feel like it’s pretty lousy not to patch them as well.
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BIOS updates are the only way to receive critical stability and security patches. They can take a bit of time, but these days its generally pretty straight forward. Some manufacturers even allow you to check online right from the UEFI so you don’t need to rely on an ancient USB drive.