PrivacyPeek: Auditing What LLM-Based Agents Acquire, Not Just What They Say

Fuente: arXiv
Salvato in:
Dettagli Bibliografici
Autori principali: Zhang, Mingxuan, Han, Jiahui, Guo, Dadi, Li, Songze, Wang, Guanchu, Zou, Na, Liu, Dongrui, Hu, Xia
Natura: Preprint
Pubblicazione: 2026
Soggetti:
Accesso online:
Tags: Aggiungi Tag
Nessun Tag, puoi essere il primo ad aggiungerne!!
_version_ 1866914619448098816
author Zhang, Mingxuan
Han, Jiahui
Guo, Dadi
Li, Songze
Wang, Guanchu
Zou, Na
Liu, Dongrui
Hu, Xia
author_facet Zhang, Mingxuan
Han, Jiahui
Guo, Dadi
Li, Songze
Wang, Guanchu
Zou, Na
Liu, Dongrui
Hu, Xia
contents LLM-based agents are rapidly advancing, autonomously invoking external tools to complete multi-step tasks for users. However, agents often acquire more sensitive information than the task requires. Existing privacy benchmarks audit what the agent's response or outgoing actions disclose, but overlook the acquisition stage where data first enters the agent's context. The over-acquired information is then one careless action or one attack away from an outright leak. To assess its prevalence, we introduce \emph{PrivacyPeek}, a benchmark for evaluating acquisition-stage privacy leakage of LLM-based agents, with $1{,}182$ cases across $7$ acquisition behaviours and $16$ application domains. Specifically, \emph{Acquisition Inspection} examines the agent's tool-call trajectory, both the tools it invokes and the data it receives, to detect when it acquires sensitive information beyond the task scope. \emph{Probe Elicitation} then issues a follow-up probe and measures how readily an attacker could elicit sensitive information the agent acquired but did not disclose. Our experiments on 10 LLM-based agents across 4 model families show that the unnecessary acquisition of sensitive information is widespread. In addition, we observe a correlation between the task-completion capability and acquisition-stage leakage. Prompt-level defences reduce only a small fraction of acquisition-stage leakage, leaving the majority unmitigated. These results make auditing acquisition-stage privacy both urgent and necessary. Our dataset and code are available at https://github.com/Xuan269/PrivacyPeek-Resource.
format Preprint
id arxiv_https___arxiv_org_abs_2606_00152
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle PrivacyPeek: Auditing What LLM-Based Agents Acquire, Not Just What They Say
Zhang, Mingxuan
Han, Jiahui
Guo, Dadi
Li, Songze
Wang, Guanchu
Zou, Na
Liu, Dongrui
Hu, Xia
Cryptography and Security
Artificial Intelligence
LLM-based agents are rapidly advancing, autonomously invoking external tools to complete multi-step tasks for users. However, agents often acquire more sensitive information than the task requires. Existing privacy benchmarks audit what the agent's response or outgoing actions disclose, but overlook the acquisition stage where data first enters the agent's context. The over-acquired information is then one careless action or one attack away from an outright leak. To assess its prevalence, we introduce \emph{PrivacyPeek}, a benchmark for evaluating acquisition-stage privacy leakage of LLM-based agents, with $1{,}182$ cases across $7$ acquisition behaviours and $16$ application domains. Specifically, \emph{Acquisition Inspection} examines the agent's tool-call trajectory, both the tools it invokes and the data it receives, to detect when it acquires sensitive information beyond the task scope. \emph{Probe Elicitation} then issues a follow-up probe and measures how readily an attacker could elicit sensitive information the agent acquired but did not disclose. Our experiments on 10 LLM-based agents across 4 model families show that the unnecessary acquisition of sensitive information is widespread. In addition, we observe a correlation between the task-completion capability and acquisition-stage leakage. Prompt-level defences reduce only a small fraction of acquisition-stage leakage, leaving the majority unmitigated. These results make auditing acquisition-stage privacy both urgent and necessary. Our dataset and code are available at https://github.com/Xuan269/PrivacyPeek-Resource.
title PrivacyPeek: Auditing What LLM-Based Agents Acquire, Not Just What They Say
topic Cryptography and Security
Artificial Intelligence
url https://arxiv.org/abs/2606.00152