AMD Processors Entropy Degradation Vulnerability in RDRAND Instruction for SEV-SNP Guests

A vulnerability exists in certain AMD processors due to incomplete cleanup after loading CPU microcode patches. This flaw may allow a privileged attacker to degrade the entropy of the RDRAND instruction, potentially compromising the integrity of SEV-SNP (Secure Encrypted Virtualization - Secure Nested Paging) guests. The issue affects several AMD EPYC and Ryzen processor series.

Impact

Exploitation of this vulnerability could lead to a degradation of entropy in the RDRAND instruction, causing a potential loss of integrity for SEV-SNP guests.

Remediation

Users are advised to update to the latest Platform Initialization (PI) firmware version. Specific update instructions can be obtained from the original equipment manufacturer (OEM).