AMD Transient Scheduler Attacks for “Zen 5” Processors

Summary

This security notice is a follow-up to AMD-SN-7029 and includes mitigations for AMD Zen5 processors.

As described in AMD-SN-7029, AMD assessed that CVE-2024-36350 (TSA-SQ) could allow an attacker to infer data from previous stores, potentially resulting in Kernel-to-User data leakage. AMD also assessed that CVE-2024-36357 (TSA-L1) could allow an attacker to infer data from the L1 data cache, potentially resulting in leakage of sensitive information across privileged boundaries such as host-to-guest, guest-to-guest, kernel-to-user, and user-to-user contexts.

Subsequent investigation determined that AMD Zen 5 processors are impacted differently from previously characterized AMD processors. As a result, AMD developed and is releasing additional Platform Initialization (PI) firmware package updates and corresponding mitigations for affected Zen 5 products. PI firmware and operating system updates are required to fully mitigate the applicable TSA vulnerabilities on affected platforms.

References

Acknowledgement 

AMD thanks Oleksii Oleksenko, Cedric Fournet, Jana Hofmann, Boris Köpf, Stavros Volos from Microsoft, and Flavien Solt from ETH Zurich for reporting these issues and engaging in coordinated vulnerability disclosure.

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