Preface: AMD EPYC processors are extensively used for High-Performance Computing (HPC) clusters, powering some of the world’s most advanced supercomputers. They are specifically engineered to handle compute-intensive tasks such as scientific simulations, weather forecasting, and complex molecular modelling.
Background: AMD Infinity Guard is a suite of security features built directly into the silicon of the AMD EPYC processor. While it interacts with and protects firmware, its foundation is hardware-based. When AMD Infinity Guard forms Secure Encrypted Virtualization (SEV), the encryption keys are not stored on an external hard disk or in standard bare-metal memory. Instead, they are kept entirely within the processor’s hardware. The actual data belonging to your virtual machine is stored in the system’s “bare-metal” RAM (DRAM), but it is fully encrypted.
In a traditional setup, the hypervisor has “God mode”—it can see everything. With AMD SEV-SNP, the hardware creates a Trusted Execution Environment (TEE) where the hypervisor is demoted to a simple “data mover” that is cryptographically blocked from the VM’s secrets.
Ref: CounterSEVeillance is a novel side-channel attack that targets AMD SEV-SNP (Secure Encrypted Virtualization-Secure Nested Paging), a technology designed to protect confidential virtual machines (VMs) from a malicious hypervisor. Unlike previous attacks that might manipulate the VM’s state, CounterSEVeillance is primarily a passive side-channel attack, making it difficult to detect.
Official article details
Summary: Researchers from Universities of Durham and of Luebeck have reported a way for a malicious hypervisor to monitor performance counters and potentially recover data from a guest VM.
Affected Products and Mitigation: Performance counters are not protected by Secure Encrypted Virtualization (SEV, SEV-ES, or SEV-SNP). AMD has defined support for performance counter virtualization in APM Vol 2, section 15.39. Performance Monitoring Counters (PMC) virtualization, available on AMD products starting with AMD EPYC™ 9005 Series Processors, is designed to protect performance counters from the type of monitoring described by the researchers.
For processors released prior to AMD EPYC™ 9005 Series Processors, AMD recommends software developers employ existing best practices, including avoiding secret-dependent data access or control flows where appropriate to help mitigate this potential vulnerability.
Official announcement: Please refer to the link for details –
https://www.amd.com/en/resources/product-security/bulletin/amd-sb-3042.html