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arXiv:2501.12890cs.CR

Analyzing and Exploiting Branch Mispredictions in Microcode

Nicholas Mosier, Hamed Nemati, John C. Mitchell, Caroline Trippel

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Abstract

We present uSpectre, a new class of transient execution attacks that exploit microcode branch mispredictions to transiently leak sensitive data. We find that many long-known and recently-discovered transient execution attacks, which were previously categorized as Spectre or Meltdown variants, are actually instances of uSpectre on some Intel microarchitectures. Based on our observations, we discover multiple new uSpectre attacks and present a defense against uSpectre vulnerabilities, called uSLH.

arXiv comments
Journal reference
DOI
Subjects
cs.CRCryptography and Security cs.ARHardware Architecture

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Linked by 1 identifiable commenter in 1 comment across 1 thread, from Mar 2025 to Mar 2025. Found in 2 HN submissions from Jan 2025 to Jan 2025. Open submission discussions.

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  1. Zentool – AMD Zen Microcode Manipulation Utility 1 comment

    • It's not especially likely you'll be able to make things faster unless you're really strapped for fetch bandwidth. The reasoning is that most useful uops will already have instructions which directly decode to them (ie you're not going to get a faster load with ucode than if you…

      sweetjulyView on HNParent context

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