BEAT: Visual Backdoor Attacks on VLM-based Embodied Agents via Contrastive Trigger Learning

Fuente: arXiv
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Main Authors: Zhan, Qiusi, Ha, Hyeonjeong, Yang, Rui, Xu, Sirui, Chen, Hanyang, Gui, Liang-Yan, Wang, Yu-Xiong, Zhang, Huan, Ji, Heng, Kang, Daniel
Format: Preprint
Published: 2025
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author Zhan, Qiusi
Ha, Hyeonjeong
Yang, Rui
Xu, Sirui
Chen, Hanyang
Gui, Liang-Yan
Wang, Yu-Xiong
Zhang, Huan
Ji, Heng
Kang, Daniel
author_facet Zhan, Qiusi
Ha, Hyeonjeong
Yang, Rui
Xu, Sirui
Chen, Hanyang
Gui, Liang-Yan
Wang, Yu-Xiong
Zhang, Huan
Ji, Heng
Kang, Daniel
contents Recent advances in Vision-Language Models (VLMs) have propelled embodied agents by enabling direct perception, reasoning, and planning task-oriented actions from visual inputs. However, such vision-driven embodied agents open a new attack surface: visual backdoor attacks, where the agent behaves normally until a visual trigger appears in the scene, then persistently executes an attacker-specified multi-step policy. We introduce BEAT, the first framework to inject such visual backdoors into VLM-based embodied agents using objects in the environments as triggers. Unlike textual triggers, object triggers exhibit wide variation across viewpoints and lighting, making them difficult to implant reliably. BEAT addresses this challenge by (1) constructing a training set that spans diverse scenes, tasks, and trigger placements to expose agents to trigger variability, and (2) introducing a two-stage training scheme that first applies supervised fine-tuning (SFT) and then our novel Contrastive Trigger Learning (CTL). CTL formulates trigger discrimination as preference learning between trigger-present and trigger-free inputs, explicitly sharpening the decision boundaries to ensure precise backdoor activation. Across various embodied agent benchmarks and VLMs, BEAT achieves attack success rates up to 80%, while maintaining strong benign task performance, and generalizes reliably to out-of-distribution trigger placements. Notably, compared to naive SFT, CTL boosts backdoor activation accuracy up to 39% under limited backdoor data. These findings expose a critical yet unexplored security risk in VLM-based embodied agents, underscoring the need for robust defenses before real-world deployment.
format Preprint
id arxiv_https___arxiv_org_abs_2510_27623
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle BEAT: Visual Backdoor Attacks on VLM-based Embodied Agents via Contrastive Trigger Learning
Zhan, Qiusi
Ha, Hyeonjeong
Yang, Rui
Xu, Sirui
Chen, Hanyang
Gui, Liang-Yan
Wang, Yu-Xiong
Zhang, Huan
Ji, Heng
Kang, Daniel
Artificial Intelligence
Computation and Language
Computer Vision and Pattern Recognition
Recent advances in Vision-Language Models (VLMs) have propelled embodied agents by enabling direct perception, reasoning, and planning task-oriented actions from visual inputs. However, such vision-driven embodied agents open a new attack surface: visual backdoor attacks, where the agent behaves normally until a visual trigger appears in the scene, then persistently executes an attacker-specified multi-step policy. We introduce BEAT, the first framework to inject such visual backdoors into VLM-based embodied agents using objects in the environments as triggers. Unlike textual triggers, object triggers exhibit wide variation across viewpoints and lighting, making them difficult to implant reliably. BEAT addresses this challenge by (1) constructing a training set that spans diverse scenes, tasks, and trigger placements to expose agents to trigger variability, and (2) introducing a two-stage training scheme that first applies supervised fine-tuning (SFT) and then our novel Contrastive Trigger Learning (CTL). CTL formulates trigger discrimination as preference learning between trigger-present and trigger-free inputs, explicitly sharpening the decision boundaries to ensure precise backdoor activation. Across various embodied agent benchmarks and VLMs, BEAT achieves attack success rates up to 80%, while maintaining strong benign task performance, and generalizes reliably to out-of-distribution trigger placements. Notably, compared to naive SFT, CTL boosts backdoor activation accuracy up to 39% under limited backdoor data. These findings expose a critical yet unexplored security risk in VLM-based embodied agents, underscoring the need for robust defenses before real-world deployment.
title BEAT: Visual Backdoor Attacks on VLM-based Embodied Agents via Contrastive Trigger Learning
topic Artificial Intelligence
Computation and Language
Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2510.27623