The Verifiable Action Card: Trustworthy Human-in-the-Loop Control for Secure Autonomous Agents
Verifiable Action Card architecture blocks indirect prompt injection in agentic browsers, cutting attack success from 68-100% to 0%.
Researchers propose VAC, a browser-architecture defense that reconstructs approval prompts from the ground-truth pending action and trusted intent provenance, rendering them out-of-band in trusted browser chrome. On a 24-scenario benchmark covering confused-deputy attacks, dialog forging, and indirect prompt injection, attack success fell from 68-100% to 0% across evaluated LLMs, with 78% legitimate-task completion and a 0% false-block rate. Approval is bound to the exact action re-verified at dispatch.
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