arXiv:2507.13255cs.CLcs.AI2025-07EMNLP被引 17

不微调模型就能让多模态大模型更安全,自动识别并阻断有害输出。

Automating Steering for Safe Multimodal Large Language Models

  • 用安全感知分数自动定位模型中危险信号的关键层
  • 在推理阶段检测到高风险时,通过轻量干预模块拒绝生成有害内容
  • 适用于需要安全防护的多模态应用,如内容审核与对话系统

多模态大语言模型(MLLMs)虽具备强大的跨模态推理能力,但面对对抗性多模态输入时也带来新的安全风险。为提升推理阶段的安全性,我们提出无需微调底层模型的模块化自适应干预技术 AutoSteer。该技术包含三个核心组件:(1) 新提出的安全意识评分(SAS),可自动识别模型内部层中最具安全相关性的差异;(2) 一个训练用于估计中间表示产生有毒输出概率的自适应安全探测器;(3) 一个轻量级拒绝头,在检测到安全风险时选择性干预生成过程。在 LLaVA-OV 与 Chameleon 上的实验表明,AutoSteer 显著降低了文本、视觉及跨模态威胁的攻击成功率(ASR),同时保持了模型的通用能力。结果表明,AutoSteer 是一种实用、可解释且有效的多模态AI安全部署框架。

原文摘要 · Abstract (English)

Recent progress in Multimodal Large Language Models (MLLMs) has unlocked powerful cross-modal reasoning abilities, but also raised new safety concerns, particularly when faced with adversarial multimodal inputs. To improve the safety of MLLMs during inference, we introduce a modular and adaptive inference-time intervention technology, AutoSteer, without requiring any fine-tuning of the underlying model. AutoSteer incorporates three core components: (1) a novel Safety Awareness Score (SAS) that automatically identifies the most safety-relevant distinctions among the model's internal layers; (2) an adaptive safety prober trained to estimate the likelihood of toxic outputs from intermediate representations; and (3) a lightweight Refusal Head that selectively intervenes to modulate generation when safety risks are detected. Experiments on LLaVA-OV and Chameleon across diverse safety-critical benchmarks demonstrate that AutoSteer significantly reduces the Attack Success Rate (ASR) for textual, visual, and cross-modal threats, while maintaining general abilities. These findings position AutoSteer as a practical, interpretable, and effective framework for safer deployment of multimodal AI systems.

多模态安全推理干预大模型防御

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