ID-Free Not Risk-Free: LLM-Powered Agents Unveil Risks in ID-Free Recommender Systems

Recent advances in ID-free recommender systems have attracted significant attention for effectively addressing the cold start problem. However, their vulnerability to malicious attacks remains largely unexplored. In this paper, we unveil a critical yet overlooked risk: LLM-powered agents can be strategically deployed to attack ID-free recommenders, stealthily promoting low-quality items in black-box settings. This attack exploits a novel rewriting-based deception strategy, where malicious agents synthesize deceptive textual descriptions by simulating the characteristics of popular items. To achieve this, the attack mechanism integrates two primary components: (1) a popularity extraction component that captures essential characteristics of popular items and (2) a multi-agent collaboration mechanism that enables iterative refinement of promotional textual descriptions through independent thinking and team discussion. To counter this risk, we further introduce a detection method to identify suspicious text generated by our discovered attack. By unveiling this risk, our work aims to underscore the urgent need to enhance the security of ID-free recommender systems.

@article{wang2025_2409.11690,
  title={ ID-Free Not Risk-Free: LLM-Powered Agents Unveil Risks in ID-Free Recommender Systems },
  author={ Zongwei Wang and Min Gao and Junliang Yu and Xinyi Gao and Quoc Viet Hung Nguyen and Shazia Sadiq and Hongzhi Yin },
  journal={arXiv preprint arXiv:2409.11690},
  year={ 2025 }
}