Probabilistic Modeling of Jailbreak on Multimodal LLMs: From Quantification to Application

Fuente: arXiv
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Autori principali: Xu, Wenzhuo, Wei, Zhipeng, Sun, Xiongtao, Ying, Zonghao, Zhang, Deyue, Yang, Dongdong, Zhang, Xiangzheng, Zou, Quanchen
Natura: Preprint
Pubblicazione: 2025
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author Xu, Wenzhuo
Wei, Zhipeng
Sun, Xiongtao
Ying, Zonghao
Zhang, Deyue
Yang, Dongdong
Zhang, Xiangzheng
Zou, Quanchen
author_facet Xu, Wenzhuo
Wei, Zhipeng
Sun, Xiongtao
Ying, Zonghao
Zhang, Deyue
Yang, Dongdong
Zhang, Xiangzheng
Zou, Quanchen
contents Recently, Multimodal Large Language Models (MLLMs) have demonstrated their superior ability in understanding multimodal content. However, they remain vulnerable to jailbreak attacks, which exploit weaknesses in their safety alignment to generate harmful responses. Previous studies categorize jailbreaks as successful or failed based on whether responses contain malicious content. However, given the stochastic nature of MLLM responses, this binary classification of an input's ability to jailbreak MLLMs is inappropriate. Derived from this viewpoint, we introduce jailbreak probability to quantify the jailbreak potential of an input, which represents the likelihood that MLLMs generated a malicious response when prompted with this input. We approximate this probability through multiple queries to MLLMs. After modeling the relationship between input hidden states and their corresponding jailbreak probability using Jailbreak Probability Prediction Network (JPPN), we use continuous jailbreak probability for optimization. Specifically, we propose Jailbreak-Probability-based Attack (JPA) that optimizes adversarial perturbations on input image to maximize jailbreak probability, and further enhance it as Multimodal JPA (MJPA) by including monotonic text rephrasing. To counteract attacks, we also propose Jailbreak-Probability-based Finetuning (JPF), which minimizes jailbreak probability through MLLM parameter updates. Extensive experiments show that (1) (M)JPA yields significant improvements when attacking a wide range of models under both white and black box settings. (2) JPF vastly reduces jailbreaks by at most over 60\%. Both of the above results demonstrate the significance of introducing jailbreak probability to make nuanced distinctions among input jailbreak abilities.
format Preprint
id arxiv_https___arxiv_org_abs_2503_06989
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Probabilistic Modeling of Jailbreak on Multimodal LLMs: From Quantification to Application
Xu, Wenzhuo
Wei, Zhipeng
Sun, Xiongtao
Ying, Zonghao
Zhang, Deyue
Yang, Dongdong
Zhang, Xiangzheng
Zou, Quanchen
Cryptography and Security
Computer Vision and Pattern Recognition
Recently, Multimodal Large Language Models (MLLMs) have demonstrated their superior ability in understanding multimodal content. However, they remain vulnerable to jailbreak attacks, which exploit weaknesses in their safety alignment to generate harmful responses. Previous studies categorize jailbreaks as successful or failed based on whether responses contain malicious content. However, given the stochastic nature of MLLM responses, this binary classification of an input's ability to jailbreak MLLMs is inappropriate. Derived from this viewpoint, we introduce jailbreak probability to quantify the jailbreak potential of an input, which represents the likelihood that MLLMs generated a malicious response when prompted with this input. We approximate this probability through multiple queries to MLLMs. After modeling the relationship between input hidden states and their corresponding jailbreak probability using Jailbreak Probability Prediction Network (JPPN), we use continuous jailbreak probability for optimization. Specifically, we propose Jailbreak-Probability-based Attack (JPA) that optimizes adversarial perturbations on input image to maximize jailbreak probability, and further enhance it as Multimodal JPA (MJPA) by including monotonic text rephrasing. To counteract attacks, we also propose Jailbreak-Probability-based Finetuning (JPF), which minimizes jailbreak probability through MLLM parameter updates. Extensive experiments show that (1) (M)JPA yields significant improvements when attacking a wide range of models under both white and black box settings. (2) JPF vastly reduces jailbreaks by at most over 60\%. Both of the above results demonstrate the significance of introducing jailbreak probability to make nuanced distinctions among input jailbreak abilities.
title Probabilistic Modeling of Jailbreak on Multimodal LLMs: From Quantification to Application
topic Cryptography and Security
Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2503.06989