AMD SinkClose Flaw Lets Attackers Bypass SMM Protections on CPUs Since 2006
Vulnerability Disclosure · 2 sources · Updated 3mo ago · First seen Aug 14, 2024
AMD disclosed the high-severity SinkClose processor vulnerability, tracked as CVE-2023-31315, affecting a broad range of AMD CPUs manufactured since 2006. The flaw can be exploited by an attacker who already has kernel-level access to manipulate System Management Mode (SMM) configuration, bypass SMM lock protections, and execute arbitrary code at the highly privileged Ring -2 level.
Researchers Enrique Nissim and Krzysztof Okupski of IOActive showed multiple exploitation paths, including abuse of the TSeg protection mechanism and access to sensitive data stored in SMRAM. AMD directed customers to obtain product-specific BIOS updates from their OEM or system vendor as the primary mitigation for affected platforms.
