One Shot Dominance: Knowledge Poisoning Attack on Retrieval-Augmented Generation Systems

Zhiyuan Chang, Mingyang Li, Xiaojun Jia, Junjie Wang, Yuekai Huang, Ziyou Jiang, Yang Liu, Qing Wang


Abstract
Large Language Models (LLMs) enhanced with Retrieval-Augmented Generation (RAG) have shown improved performance in generating accurate responses. However, the dependence on external knowledge bases introduces potential security vulnerabilities, particularly when these knowledge bases are publicly accessible and modifiable. While previous studies have exposed knowledge poisoning risks in RAG systems, existing attack methods suffer from critical limitations: they either require injecting multiple poisoned documents (resulting in poor stealthiness) or can only function effectively on simplistic queries (limiting real-world applicability). This paper reveals a more realistic knowledge poisoning attack against RAG systems that achieves successful attacks by poisoning only a single document while remaining effective for complex multi-hop questions involving complex relationships between multiple elements. Our proposed AuthChain address three challenges to ensure the poisoned documents are reliably retrieved and trusted by the LLM, even against large knowledge bases and LLM’s own knowledge. Extensive experiments across six popular LLMs demonstrate that AuthChain achieves significantly higher attack success rates while maintaining superior stealthiness against RAG defense mechanisms compared to state-of-the-art baselines.
Anthology ID:
2025.findings-emnlp.1023
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2025
Month:
November
Year:
2025
Address:
Suzhou, China
Editors:
Christos Christodoulopoulos, Tanmoy Chakraborty, Carolyn Rose, Violet Peng
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
18811–18825
Language:
URL:
https://aclanthology.org/2025.findings-emnlp.1023/
DOI:
Bibkey:
Cite (ACL):
Zhiyuan Chang, Mingyang Li, Xiaojun Jia, Junjie Wang, Yuekai Huang, Ziyou Jiang, Yang Liu, and Qing Wang. 2025. One Shot Dominance: Knowledge Poisoning Attack on Retrieval-Augmented Generation Systems. In Findings of the Association for Computational Linguistics: EMNLP 2025, pages 18811–18825, Suzhou, China. Association for Computational Linguistics.
Cite (Informal):
One Shot Dominance: Knowledge Poisoning Attack on Retrieval-Augmented Generation Systems (Chang et al., Findings 2025)
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PDF:
https://aclanthology.org/2025.findings-emnlp.1023.pdf
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