arXiv AI By Zehua Zhang, Jie Hu, Pratham Hegde, Aditya Maheshbhai Gabani, Souradip Nath, Yibo Liu, Siyu Liu, Hongkai Chen, Hulin Wang, Zhuoer Lyu, Chang Zhu, Divij Handa, Yan Shoshitaishvili, Tiffany Bao, Ruoyu Wang, Adam Doupe

No-Box Vulnerability Analysis: Description-only Detection of Indirect Prompt Injection Vulnerabilities in MCP Servers

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The paper introduces no‑box vulnerability analysis, a method that detects security flaws without system access or runtime interaction by examining only the functionality metadata of a target. Using this approach, the authors built MCPSEC to audit Model Context Protocol servers for indirect prompt injection vulnerabilities, evaluating it on 20 servers with 177 tools. MCPSEC identified 143 vulnerable tools, achieving 98.9% recall of verified vulnerabilities, outperforming an LLM baseline.

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