提升大模型越狱攻击效率,用更少尝试达成更高成功率
Faster-GCG: Efficient Discrete Optimization Jailbreak Attacks against Aligned Large Language Models
- 改进梯度估计、动态采样和去重机制,优化离散优化流程
- 仅需3.2万次评估即达78.1%成功率,效率提升8倍
- 适合研究模型安全与对抗攻击的从业者快速验证
对齐的大语言模型因其安全性受到广泛关注,尤其在越狱攻击试图通过对抗性提示绕过安全防护的背景下。现有方法中,贪婪坐标梯度(GCG)通过离散令牌优化实现了自动化越狱,但其样本效率低,每种有害行为需约25.6万次评估才能达到满意成功率,源于底层离散优化问题的固有难度。本文识别出限制GCG样本效率的三个关键因素:不准确的梯度估计、低效的均匀采样以及重复评估已探索后缀。为此提出Faster-GCG,通过距离正则化改善估计,温度控制采样提升探索效率,并引入已访问后缀标记机制避免冗余评估。Faster-GCG将所需评估次数降至3.2万次,实现高达8倍的采样效率提升和7倍的运行时间减少。在此预算下,其在五款对齐大模型上平均越狱成功率达78.1%,对Qwen3.5-4B达到88.7%,优于当前最优白盒越狱方法。
原文摘要 · Abstract (English)
Aligned Large Language Models (LLMs) have attracted significant attention for their safety, particularly in the context of jailbreak attacks that attempt to bypass guardrails via adversarial prompts. Among existing approaches, the Greedy Coordinate Gradient (GCG) attack pioneered automated jailbreaks through discrete token optimization; however, its low sample efficiency limits practical applicability. In particular, GCG requires approximately 256K evaluations per harmful behavior to achieve a satisfactory jailbreak success rate, due to the inherent difficulty of the underlying discrete optimization problem. In this work, we identify three key factors that limit the sample efficiency of GCG: inaccurate gradient-based estimation, inefficient uniform sampling, and repeated evaluation of previously explored suffixes. To address these issues, we propose Faster-GCG, a streamlined variant of GCG that incorporates distance-based regularization for improved estimation, temperature-controlled sampling for more effective exploration, and a visited-suffix marking mechanism to avoid redundant evaluations. Faster-GCG reduced the required evaluations to 32K, achieving up to an $8\times$ improvement in sampling efficiency and a $7\times$ reduction in wall-clock time compared to GCG. Under this reduced budget, Faster-GCG attained an average jailbreak success rate of 78.1\% across five aligned LLMs, and achieved 88.7\% against Qwen3.5-4B, outperforming state-of-the-art white-box jailbreak methods.
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