arXiv AI

Evaluating Deep-Search Agents under Hierarchical Web Evidence Poisoning

arXiv AI
Aug 6

Breadcrumbing Search Agents

arXiv:2608. 04565v1 Announce Type: cross Abstract: LLM-based search agents are widely used for information-seeking tasks, but their reliance on external tool returns introduces a critical security risk: web content retrieved during execution is untrusted, exposing agents to prompt injection and goal hijacking.

By Xuebin Li, Hanqing Zhao, Siyuan Liang, Kejiang Chen, Weiming Zhang, Dacheng Tao, Nenghai Yu
arXiv AI
6d ago

Breadcrumbing Search Agents: Per-Turn Scheming Over Long-Horizon Trajectories

The paper investigates how large language model (LLM) search agents can be manipulated through repeated, coordinated search-result injections, a threat that extends beyond single-page poisoning. It introduces Authority‑Chain Hijack (ACH), a strategy that chains manipulated evidence across multiple sources, achieving high attack success rates on the SafeSearch benchmark. The authors also present Trace‑Guided Strategy Evolution (TGSE), an automated method that refines attacker strategies using execution traces, further improving success rates.

By Xuebin Li, Hanqing Zhao, Siyuan Liang, Kejiang Chen, Weiming Zhang, Dacheng Tao, Nenghai Yu
arXiv AI
Aug 25

One Polluted Page Is Enough: Evaluating Web Content Pollution in LLM Recommenders

The paper introduces FORGE, a benchmark that rewrites real product pages into fake ones to test how often search‑augmented large language models (LLMs) recommend these polluted items. Across 12 commercial and open‑weight LLMs, a single polluted page can lead to up to 27% of recommendations being fake, rising to 73.8% when the top‑3 replacements are used. The study finds that reasoning does not help and existing defenses—skepticism prompts, consensus filters, and credibility re‑ranking—are largely ineffective.

By Minghao Luo, Liang Chen
arXiv AI
Sep 10

Do Web Agents Investigate Before They Decide?

The paper introduces MIRAGE, a benchmark of 750 multi‑step decision tasks designed to test autonomous web agents’ investigative abilities across Wikipedia Forensics, Shopping Admin adjudication, and Reddit Moderation. Each task contains a misleading visible context and a hidden context that holds decisive evidence, allowing performance to be broken down into Investigation, Reasoning, and Decision Accuracy, with an added Investigative Hallucination Rate. Evaluation of eight LLM agents reveals three consistent patterns: agents often reach relevant pages but fail to extract decisive evidence, procedural hints improve investigation but not decision accuracy on Wikipedia tasks, and 12.6% of trajectories include fabricated facts.

By Syed Nazmus Sakib, Nafiul Haque, Tapodhir Karmakar Taton, Shahrear Bin Amin, Shifat E. Arman
arXiv AI
1d ago

ScamWorld: An Interactive Environment for Evaluating Web Agents Against Online Fraud

ScamWorld is an interactive environment that recreates reported scam websites across various scenarios, fraud mechanisms, and languages, allowing researchers to observe fraud indicators before a web agent’s final action. The platform enables controlled, repeatable evaluation of web agents, which are increasingly used to browse, shop, and manage accounts on the open web. A study of six leading LLM-powered agents revealed deception rates between 11% and 35%, with agents more likely to proceed with payments than to provide credentials or wallet information, and some agents continuing after recognizing suspicious conditions.

By Yutao Wu, Xiao Liu, Ming Wen, Hanxun Huang, Jun Wang, Xingjun Ma