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.”
Iiuc to exploit you already need kernel level access. I’d figure if something malicious made it that far, you’re already screwed.