AMD has released critical security updates to patch a high-severity vulnerability (CVE-2024-56161) affecting multiple processor generations. The flaw, discovered by Google’s Security Team, stems from an improper signature verification in AMD’s CPU ROM microcode patch loader.

Impact and Technical Details:
– Affects AMD processors from Zen 1 through Zen 4 architectures
– Compromises AMD’s Secure Encrypted Virtualization-Secure Nested Paging (SEV-SNP)
– Enables attackers with local admin privileges to execute malicious microcode
– Impacts data confidentiality and integrity in secure environments

Affected Processors:
– EPYC 7001 Series (Naples)
– EPYC 7002 Series (Rome)
– EPYC 7003 Series (Milan/Milan-X)
– EPYC 9004 Series (Genoa/Genoa-X/Bergamo/Siena)

Mitigation Steps:
1. Install the latest microcode update
2. Update SEV firmware where required
3. Update system BIOS
4. Perform system reboot
5. Verify microcode version matches AMD’s specifications

Additional Security Concern:
A separate report from National Taiwan University identified cache-based side-channel attacks affecting AMD’s SEV implementation across multiple EPYC processor generations. AMD recommends implementing constant-time algorithms and following Spectre-attack mitigation guidelines.

Users are strongly advised to apply these security updates promptly to protect against potential exploits and maintain system security.