Branch History Leak
AMD ID: AMD-SB-7026
Potential Impact: N/A
Severity: N/A
Summary
Researchers from The Harbin Institute of Technology have shared with AMD a paper titled “Branch History LeakeR: Leveraging Branch History to Construct a New Side Channel-Theory and Practice” that demonstrates a side channel attack using the Global History Register (GHR). The GHR is used to assist in conditional branch prediction. The researchers note that the GHR is shared between different security domains and may retain data after a security domain switch. After a return to the user-space, the researchers were able to infer the direction of recently executed conditional branches.
AMD believes this attack is similar to previously disclosed side-channel attacks and that existing mitigation recommendations for such attacks remain applicable.
Mitigation
AMD recommends software developers employ existing best practices, including constant-time algorithms and avoiding secret-dependent data accesses or control flows where appropriate to help mitigate this potential vulnerability.
Acknowledgement
AMD thanks Zikang Tao, Rihui Sun, and Jian Dong of Harbin Institute of Technology for reporting this issue and engaging in coordinated vulnerability disclosure.
Revisions
Revision Date |
Description |
2025-03-27 |
Initial publication |
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