Assessing the Brittleness of Safety Alignment via Pruning and Low-Rank
  Modifications
Boyi Wei Kaixuan Huang Yangsibo Huang Tinghao Xie Xiangyu Qi Mengzhou Xia Prateek Mittal Mengdi Wang Peter Henderson
Large language models (LLMs) show inherent brittleness in their safety
mechanisms, as evidenced by their susceptibility to jailbreaking and even
non-malicious fine-tuning. This study explores this brittleness of safety
alignment by leveraging pruning and low-rank modifications. We develop methods
to identify critical regions that are vital for safety guardrails, and that are
disentangled from utility-relevant regions at both the neuron and rank levels.
Surprisingly, the isolated regions we find are sparse, comprising about $3\%$
at the parameter level and $2.5\%$ at the rank level. Removing these regions
compromises safety without significantly impacting utility, corroborating the
inherent brittleness of the model's safety mechanisms. Moreover, we show that
LLMs remain vulnerable to low-cost fine-tuning attacks even when modifications
to the safety-critical regions are restricted. These findings underscore the
urgent need for more robust safety strategies in LLMs.