AMD SEV-SNP Improper Access Control Vulnerability Allowing Memory Integrity Corruption

A vulnerability exists in AMD Secure Encrypted Virtualization - Secure Nested Paging (SEV-SNP) due to improper access control. This issue could enable an admin-privileged attacker to write to the Reverse Map Table (RMP) during the initialization phase of SEV-SNP, potentially compromising the integrity of guest memory. The vulnerability arises from a race condition that can be exploited by a malicious hypervisor to manipulate the initial RMP content, leading to a loss of memory integrity for SEV-SNP guests.

Impact

Exploitation of this vulnerability could allow a malicious hypervisor to corrupt the Reverse Map Table, manipulating the memory integrity of SEV-SNP guests.

Remediation

Users are advised to update to the recommended SEV Firmware or Platform Initialization (PI) firmware version. Specific guidance can be found in the AMD Security Bulletin AMD-SB-3020.