A vulnerability exists in the quantization process of Large Language Models (LLMs) that allows an attacker to inject malicious behavior into a quantized model, even if the full-precision model appears benign. The attack leverages the discrepancy between full-precision and quantized model behavior introduced by quantization methods such as LLM.int8(), NF4, and FP4. An attacker can fine-tune a model to exhibit malicious behavior when quantized, then use projected gradient descent to remove the…
Source: arXiv