Shipped: Multi-Agent Steganographic Prompt Injection Defense
Proof-of-concept that shows how a malicious instruction hidden in an image (LSB steganography) can be extracted and executed by a multi-agent system. Uses a Coordinator + 4 Workers + Verifier architecture over real MCP tools, with a local Qwen model driving agent decisions. Demonstrates a vulnerable path (stego-extracted text treated as trusted) and a protected path (source tagging + policy blocking of critical tools). Includes before/after visualization of the cover image and an email-attachment attack scenario.
multi-agentMCP steganographyprompt-injectionAI-securityagentic-AI QwenHugging-FaceColabLSB
1 comment
Source tagging plus blocking critical tools is a sensible split, since the stego decode itself can't be reliably prevented. With a 0.5B Qwen driving decisions, does the Verifier catch the attack on its own, or does the policy layer do all the work? I'd also like to know if a stronger model changes that.