Using Mechanistic Interpretability to Craft Adversarial Attacks against
  Large Language Models
Authors: name: Thomas Winninger; name: Boussad Addad; name: Katarzyna Kapusta
Published: 2025-03-08 16:29:45

Abstract: Traditional white-box methods for creating adversarial perturbations against
LLMs typically rely only on gradient computation from the targeted model,
ignoring the internal mechanisms responsible for attack success or failure.
Conversely, interpretability studies that analyze these internal mechanisms
lack practical applications beyond runtime interventions. We bridge this gap by
introducing a novel white-box approach that leverages mechanistic
interpretability techniques to craft practical adversarial inputs.
Specifically, we first identify acceptance subspaces - sets of feature vectors
that do not trigger the model's refusal mechanisms - then use gradient-based
optimization to reroute embeddings from refusal subspaces to acceptance
subspaces, effectively achieving jailbreaks. This targeted approach
significantly reduces computation cost, achieving attack success rates of
80-95\% on state-of-the-art models including Gemma2, Llama3.2, and Qwen2.5
within minutes or even seconds, compared to existing techniques that often fail
or require hours of computation. We believe this approach opens a new direction
for both attack research and defense development. Furthermore, it showcases a
practical application of mechanistic interpretability where other methods are
less efficient, which highlights its utility. The code and generated datasets
are available at https://github.com/Sckathach/subspace-rerouting.