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Google’s security researchers have noted a serious security gap in all AMD Zen processors, ranging from Zen 1 to Zen 4. With local administrator access, attackers can inject malicious microcode patches that can put all computing workloads at risk concerning confidentiality and integrity. The target CPUs exploited microcode signature checks by using hash techniques that are known to be weak.
The vulnerability poses a serious risk, particularly to environments that rely on AMD’s Secure Encrypted Virtualization and Dynamic Root of Trust Measurement. By manipulating microcode updates, attackers could bypass security measures, gaining unauthorized access to sensitive data.
Google first notified AMD of the issue on September 25, 2024. In response, AMD developed and distributed an embargoed fix to its customers on December 17, 2024. To ensure users had adequate time to apply the necessary patches, Google delayed public disclosure until February 3, 2025. The company has stated that additional technical details will not be released until March 5, 2025, to prevent further exploitation before users can implement the fix.
AMD has recommended a patch for the vulnerability and in their advisory note, they describe the fixes and their implementations. In essence, they need to include a mitigative Microcode BIOS update. Users will be required to download and install required firmware packages from their OEMs of relevance to achieve such mitigation. To implement the security features and measures after the update, rebooting the system is vital.
Not applying this update poses the risk of systems coming under attack which is why mitigation has to be a priority. For those who use AMD Zen CPUs, mitigative security updates should help secure the integrity of systems while preserving the confidentiality of sensitive data.
Staying current on defense strategies is important amidst the array of cybersecurity threats. Following official communications from AMD and employing their suggested practices will help address this issue as well reduce security exposure.
