WAAA! Web Adversaries Against Agentic Browsers

Fuente: arXiv
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Main Authors: Datta, Sohom, Nahapetyan, Alex, Enck, William, Kapravelos, Alexandros
Format: Preprint
Published: 2026
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author Datta, Sohom
Nahapetyan, Alex
Enck, William
Kapravelos, Alexandros
author_facet Datta, Sohom
Nahapetyan, Alex
Enck, William
Kapravelos, Alexandros
contents Large language models (LLMs) are increasingly being integrated into web browsers to create agentic browsing systems that execute actions on behalf of the user. Prior work considering the security of agentic browsers focuses exclusively on indirect prompt-injection attacks. However, by failing to consider traditional web attacks, previous agentic browser threat models have a blind spot to web social engineering attacks originally designed to trick humans. In this paper, we propose the first web-focused threat model for agentic browsers and use it to derive a taxonomy of 20 attacks across both the web and LLM space, and implement 18 of the attacks. Our threat model extends the original See$\rightarrow$Act browser agent model to account for all components of a browser, and frames the agent as a confused deputy unable to distinguish task steps from traditional web attacks. We show that 10 web threats can reemerge often in amplified forms once an agent can be influenced by untrusted page content. We further conduct a generalizability study on 14 of the 20 attacks, showing that our attacks reproduce across 4 major LLM models spanning multiple vendors. We show that agentic browsers exhibit five major failure modes when facing traditional and LLM web threats, demonstrating the need to rearchitect agentic browsers before they are ready for the current web.
format Preprint
id arxiv_https___arxiv_org_abs_2605_05509
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle WAAA! Web Adversaries Against Agentic Browsers
Datta, Sohom
Nahapetyan, Alex
Enck, William
Kapravelos, Alexandros
Cryptography and Security
Large language models (LLMs) are increasingly being integrated into web browsers to create agentic browsing systems that execute actions on behalf of the user. Prior work considering the security of agentic browsers focuses exclusively on indirect prompt-injection attacks. However, by failing to consider traditional web attacks, previous agentic browser threat models have a blind spot to web social engineering attacks originally designed to trick humans. In this paper, we propose the first web-focused threat model for agentic browsers and use it to derive a taxonomy of 20 attacks across both the web and LLM space, and implement 18 of the attacks. Our threat model extends the original See$\rightarrow$Act browser agent model to account for all components of a browser, and frames the agent as a confused deputy unable to distinguish task steps from traditional web attacks. We show that 10 web threats can reemerge often in amplified forms once an agent can be influenced by untrusted page content. We further conduct a generalizability study on 14 of the 20 attacks, showing that our attacks reproduce across 4 major LLM models spanning multiple vendors. We show that agentic browsers exhibit five major failure modes when facing traditional and LLM web threats, demonstrating the need to rearchitect agentic browsers before they are ready for the current web.
title WAAA! Web Adversaries Against Agentic Browsers
topic Cryptography and Security
url https://arxiv.org/abs/2605.05509