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Do Internal Layers of LLMs Reveal Patterns for Jailbreak Detection?

Authors: Sri Durga Sai Sowmya Kadali, Evangelos E. Papalexakis

Published: 2025-10-08

arXiv ID: 2510.06594v1

Added to Library: 2025-10-09 04:01 UTC

Red Teaming

📄 Abstract

Jailbreaking large language models (LLMs) has emerged as a pressing concern with the increasing prevalence and accessibility of conversational LLMs. Adversarial users often exploit these models through carefully engineered prompts to elicit restricted or sensitive outputs, a strategy widely referred to as jailbreaking. While numerous defense mechanisms have been proposed, attackers continuously develop novel prompting techniques, and no existing model can be considered fully resistant. In this study, we investigate the jailbreak phenomenon by examining the internal representations of LLMs, with a focus on how hidden layers respond to jailbreak versus benign prompts. Specifically, we analyze the open-source LLM GPT-J and the state-space model Mamba2, presenting preliminary findings that highlight distinct layer-wise behaviors. Our results suggest promising directions for further research on leveraging internal model dynamics for robust jailbreak detection and defense.

🔍 Key Points

  • Investigation of internal representations of large language models (LLMs) for distinguishing between jailbreak and benign prompts using tensor decomposition methods.
  • Analysis conducted on two models: the open-source GPT-J LLM and the state-space model Mamba-2, providing insights into their layer-wise behaviors in response to different prompt types.
  • Preliminary findings demonstrate that latent features extracted via tensor decomposition effectively separate jailbreak from benign prompts, showing promise for improving jailbreak detection mechanisms.
  • A practical and straightforward framework is proposed that leverages existing classification techniques to enhance the robustness of LLMs against adversarial exploitation and jailbreaking attacks.
  • Results indicate consistent performance across models and layers, revealing that specific internal mechanisms capture more discriminative features, enhancing the reliability of using internal dynamics for security purposes.

💡 Why This Paper Matters

This paper presents significant findings in the area of LLM security by highlighting the potential of using internal model dynamics for detecting jailbreak prompts. By leveraging tensor decomposition on various layers of LLMs, the authors provide a novel approach that aids in distinguishing between malicious and benign input, which is crucial in strengthening defenses against adversarial attacks. The implications for developing more resilient language models are substantial, making this research a valuable contribution to the field.

🎯 Why It's Interesting for AI Security Researchers

The research is particularly relevant to AI security researchers as it addresses the pressing issue of jailbreaking in LLMs, which can lead to the misuse of these models for malicious purposes. The innovative approach of analyzing internal layer representations offers a new avenue for developing robust defenses against adversarial attacks. Understanding the internal dynamics of LLMs could foster the design of improved safety protocols and reinforce trust in AI systems, making the findings of this study essential for advancing AI security research.

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