~/talk

I Know What You Said: Unveiling Hardware Cache Side-Channels in Local Large

Talkat USENIX Security '25 · 2025-08-13..08-15· [large-language-models, security]
name:Zibo Gao
links:none on file
name:Junjie Hu
links:none on file
name:Feng Guo
links:none on file
links:none on file
links:none on file
links:none on file
links:none on file
links:none on file
slides:none on file

Shows a practical local attack that recovers LLM inputs and outputs by observing CPU cache behavior: embedding lookups leak token values via unique cache-line access, and autoregressive timing leaks token positions. Implementation uses mmap and flush+reload to collect traces, a PSD-based first order temporal difference preprocessor, and two fine-tuned models (LMA/LMB models) trained on synthetic traces. Evaluated on Llama, Falcon and Gemma across five LMs and 10 frameworks on consumer Intel CPUs, achieving 5.2% edit distance for outputs (17.3% for inputs) and ~98% cosine similarity; mitigations (CAT, disabling zero-copy) incur hardware or memory costs.

AI-written summary · about

  1. 0:00Cache side-channel attacks on LLMs
  2. 1:18Research questions and assumptions
  3. 2:01Token value leakage intuition
  4. 4:09Token position leakage in decoding
  5. 5:37Signal recovery challenges
  6. 6:44Attack pipeline overview
  7. 8:30Noise analysis and PSD techniques
  8. 10:15Response reconstruction with LMA
  9. 11:19Prompt reconstruction with LMB
  10. 11:59Experimental results
  11. 13:02Real-world attacks and privacy risks
  12. 13:23Mitigation strategies and future work
  13. 14:27Conclusion and privacy measures
  14. 14:49Q&A
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