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arXiv 2601.03420cs.LGcs.AIcs.CR

无需梯度或先验知识的LLM劫持:有效且可转移的攻击

Jailbreaking LLMs Without Gradients or Priors: Effective and Transferable Attacks

Department of Visual Computing, University of Bonn(视觉计算系,波恩大学);Bosch Center for Artificial Intelligence(博世人工智能中心);University of Bonn(波恩大学)

Zhakshylyk Nurlanov, Frank R. Schmidt, Florian Bernard

AI总结:

RAILS通过无需梯度或先验知识的令牌级迭代优化,实现了对LLM的有效且可转移的对抗性攻击。

摘要:

随着大型语言模型(LLMs)越来越多地应用于安全关键领域,严格评估其对对抗性劫持的鲁棒性至关重要。然而,当前的安全评估往往高估了鲁棒性,因为现有的自动化攻击受到限制性假设的制约。它们通常依赖于手工制作的先验知识或需要白盒访问才能进行梯度传播。我们挑战这些限制,通过证明在没有梯度或先验知识的情况下,令牌级迭代优化可以成功。我们引入RAILS(RAndom Iterative Local Search),一个仅基于模型logits运行的框架。RAILS通过两个关键创新实现了与基于梯度的方法相当的效果:一种新颖的自回归损失,强制精确前缀匹配,以及一种基于历史的选择策略,弥合了代理优化目标与真实攻击成功率之间的差距。关键的是,通过消除梯度依赖,RAILS使跨令牌器集成攻击成为可能。这使得能够发现在不相交词汇库中通用的对抗性模式,显著增强了转移到闭源系统的能力。实证上,RAILS在多个开源模型上实现了接近100%的成功率,并在闭源系统如GPT和Gemini上实现了高黑盒攻击可转移性。

英文摘要:

As Large Language Models (LLMs) are increasingly deployed in safety-critical domains, rigorously evaluating their robustness against adversarial jailbreaks is essential. However, current safety evaluations often overestimate robustness because existing automated attacks are limited by restrictive assumptions. They typically rely on handcrafted priors or require white-box access for gradient propagation. We challenge these constraints by demonstrating that token-level iterative optimization can succeed without gradients or priors. We introduce RAILS (RAndom Iterative Local Search), a framework that operates solely on model logits. RAILS matches the effectiveness of gradient-based methods through two key innovations: a novel auto-regressive loss that enforces exact prefix matching, and a history-based selection strategy that bridges the gap between the proxy optimization objective and the true attack success rate. Crucially, by eliminating gradient dependency, RAILS enables cross-tokenizer ensemble attacks. This allows for the discovery of shared adversarial patterns that generalize across disjoint vocabularies, significantly enhancing transferability to closed-source systems. Empirically, RAILS achieves near 100% success rates on multiple open-source models and high black-box attack transferability to closed-source systems like GPT and Gemini.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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