Bivash Nayak
30 Jul
30Jul

⚙️ Overview

As AI agents grow in complexity—performing autonomous tasks like reasoning, coding, decision-making, and even launching cyberattacks—it becomes increasingly crucial for security researchers, red teamers, and auditors to understand how these agents work under the hood.This article walks you through a complete framework to reverse engineer AI agents, uncover their decision-making pipeline, prompt logic, APIs, and potential misuse vectors.


🔍 What Is an AI Agent?

An AI agent is more than just a chatbot. It is a goal-driven autonomous system that:

  • Accepts prompts or commands
  • Plans via chains of thought (CoT)
  • Uses tools (e.g. Google, Python, Shell)
  • Executes actions in a feedback loop
  • Often uses LLMs like GPT, Claude, or LLaMA

Example: Auto-GPT, AgentGPT, LangChain Agents, OpenDevin


🎯 Why Reverse Engineer AI Agents?

ReasonPurpose
🔓 Security AuditIdentify prompt injection, SSRF, etc.
🧬 AI Behavior ForensicsUnderstand why the agent behaved a certain way
🛠️ CustomizationClone or modify the agent
🐞 Debugging / SandboxingIntercept tool calls & data flows
🧠 Model UnderstandingDeconstruct LLM reasoning paths

🔧 Reverse Engineering Framework


🧪 1. Capture Prompts & Contexts

AI agents rely heavily on system prompts, planning prompts, and memory chains.

📌 Tools:

  • 🐙 mitmproxy: Intercept API calls to OpenAI or LLMs.
  • 🧠 LangSmith: Log full prompt chains in LangChain-based agents.
  • 🪪 MemoryDump: For agents using vector memory (e.g. FAISS, Chroma).

🔎 Look For:

  • System prompt content (roles, instructions)
  • Prompt chaining logic
  • API call patterns (especially /completions, /chat)

⚙️ 2. Decompile Agent Code

Most agents are open-source or based on frameworks like LangChain, AutoGen, CrewAI, ReAct.

📁 Check:

  • Planning module (usually uses ReAct or CoT)
  • Tool calling (shell commands, browser APIs, Python exec)
  • Memory classes (long/short term)
  • RAG (Retrieval Augmented Generation) configs

🔧 Tools:

  • Ghidra (for compiled binaries)
  • Python AST (for Python-based agents)
  • Static analysis tools: pyan, bandit, radare2

🔂 3. Dynamic Tracing (Black Box Analysis)

Even if you can’t access the source code (e.g. for SaaS LLM agents), you can observe behavior dynamically.

🧰 Tools:

  • strace / lsof: Monitor file and network activity
  • API sniffers: Capture external web/DB calls
  • ptrace / frida: Hook into runtime to trace functions

🧬 4. Analyze Reasoning Paths (CoT + Logs)

Most LLM agents use Chain-of-Thought (CoT) reasoning or ReAct (Reason + Act) loop.You can reconstruct reasoning trees using:

  • Prompt outputs
  • Internal logs (LangGraph, LangChain traces)
  • Step-by-step decisions & tool usage
🧠 Pro Tip: Look for patterns like:
Thought → Action → Observation → Next Thought → Final Answer

🛡️ 5. Security Analysis: Threat Mapping

Map agent behavior to known threats:

Threat TypeVector
🧱 Prompt InjectionUser input overriding logic
🐍 Code ExecutionPython shell tool abuse
🌐 SSRF / RCEAgent calling internal URLs
📦 Plugin HijackMalicious tool integration
🧠 Data PoisoningRAG pulling malicious sources

Use MITRE ATLAS framework for LLM-specific threat mapping.


🔐 Real-World Example: Reverse Engineering Auto-GPT

  1. Forked GitHub repo
  2. Located auto_gpt_agent.py → found planning logic
  3. Intercepted calls to OpenAI API with mitmproxy
  4. Extracted system_prompt.txt → detailed chain logic
  5. Discovered memory database (memory.json)
  6. Simulated prompt injection → made agent run rm -rf /tmp/data

🎯 Deliverables of RE

After reverse engineering an agent, you can:

  • Export full prompt chain
  • Trace thought → action → output sequence
  • Map security posture
  • Build clone or defensive model

🧩 Bonus: How to Build a Honeypot AI Agent

Create a fake AI agent and:

  • Log all user prompts
  • Inject behavioral traps (e.g., fake “sudo” calls)
  • Analyze attackers trying to abuse tools or jailbreak

📘 Summary Table

StepGoalTool
Capture PromptsUnderstand prompt logicmitmproxy, LangSmith
Decompile CodeAudit core logicPython AST, Ghidra
Dynamic TraceMonitor live behaviorstrace, frida
Analyze ReasoningVisualize decisionsLangGraph
Security MapThreat detectionMITRE ATLAS, ATT&CK

📌 Final Thoughts from CyberDudeBivash

“AI agents are the new attack surface—and our job is to peel back every layer. Reverse engineering them isn't just curiosity—it's cyber defense.”
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