🛡️ Code Agent Scan

Security Audit Tooling for AI Agent Skills (Codex / Claude / MCP)

Guard your AI agents against malicious extensions, backdoors, and risky dependencies.

📖 Overview

As AI Agents (like Codex, Claude, or Goose) become more powerful, they rely on external "Skills" or "Tools" to execute code. However, installing untrusted Skills introduces significant risks: Remote Code Execution (RCE), Data Exfiltration, and Persistence.

Code Agent Scan is an automated security pipeline designed to audit these skills before you run them. It combines static analysis, Threat Intelligence (VirusTotal), and LLM-based logic review to detect hidden threats.

✨ Key Features

• 🧠 LLM-Based Logic Audit: Uses a local or API-based LLM to review code logic for complex threats (e.g., "Is this script trying to read .ssh keys?", "Does this look like a reverse shell?").
• 🌐 Threat Intelligence: Automatically extracts all URLs and Domains from the code and validates their reputation against VirusTotal.
• 🔍 Deep Inspection: Scans SKILL.md definitions and all associated scripts (scripts/*.py, scripts/*.sh, etc.).
• ⚡ Smart Caching: Caches API responses to minimize quota usage and speed up subsequent scans.
• 📊 Comprehensive Reporting: Generates both a high-level summary and a detailed line-by-line security report.

🏗️ Architecture

graph LR
    A[Skill Folder] --> B(Parser & Extractor);
    B --> C{Analysis Engine};
    C -->|IoC Check| D[VirusTotal API];
    C -->|Code Logic| E[LLM Auditor];
    D --> F[Risk Report];
    E --> F;

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🚀 Quick Start

Prerequisites

• Python 3.10+
• VirusTotal API Key (Free Public API is sufficient)

Installation

git clone https://github.com/EaEa0001/code-agent-scan.git
cd code-agent-scan
pip install -r requirements.txt

Configuration

1. Get a VirusTotal API Key:

   • Sign up for a free account at VirusTotal.
   • Go to your profile -> API Key.
   • Copy your API Key.

2. Create Config File: Create a config.json file (see config.example.json) with your key:

{
  "VT_API_KEY": "your_virustotal_key"
}

Usage

Scan a specific skill directory:

python main.py --target /path/to/.codex/skills/suspicious-skill

Scan all installed skills:

python main.py --scan-all --dir ~/.codex/skills

🚩 Detection Capabilities

We currently focus on detecting the following malicious patterns:

Category	Description
Data Exfiltration	Attempts to read sensitive files (.env, id_rsa, cookies) and send them network-side.
C2 Communication	Connections to known malicious domains, dynamic DNS, or hardcoded raw IPs.
Persistence	Modifications to .bashrc, .zshrc, registry keys, or cron jobs.
Obfuscation	Use of base64, eval(), exec(), or packed code to hide logic.
Privilege Escalation	Usage of sudo, chmod +s, or attempts to break out of sandboxes.

📝 Example Output

[+] Scanning Skill: risk-scan-virustotal
----------------------------------------
[PASS] Syntax Check
[WARN] Network: Found 1 outbound domain (virustotal.com) - Reputation: CLEAN
[FAIL] Logic: Suspicious usage of 'os.system' detected in line 42.
       > Reasoning: The script takes user input and passes it directly to shell.

🤝 Contributing

Security is a community effort. We welcome malicious test cases (submit to tests/samples), detection rules, and core improvements.

1. Fork the Project
2. Create your Feature Branch (git checkout -b feature/AmazingFeature)
3. Commit your Changes (git commit -m 'Add some AmazingFeature')
4. Push to the Branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

⚠️ Disclaimer

This tool is for defensive security purposes only. Do not use it to analyze malware on production systems without isolation. The authors are not responsible for any damage caused by the misuse of this tool.