mcp-ctf-server

MCP server that exposes common CTF and cybersecurity tools so LLMs can help with challenges in a controlled lab environment.

This is meant for capture-the-flag games and training only. Use it on systems and data you own or have explicit permission to test.

Features

Tools are grouped into categories and exposed as MCP tools:

• Crypto: gf-complete, pari-gp, rsactftool, gmp-utils
• Disk / file forensics: bulk-extractor, sleuthkit, afflib-tools, scalpel, pdfid, poppler-utils, binutils-multiarch
• Traffic forensics: wireshark, tshark, tcpflow, tcpreplay, ngrep, dsniff, bro, suricata
• Malware analysis: yara, yara-rules, clamav, upx, radare2
• Stego: steghide, stegcracker, qpdf, sox, mediainfo, gifshuffle
• Reverse engineering: python3-capstone, python3-keystone, python3-unicorn, frida-tools, radare2
• Pwn: python3-pwntools, one-gadget, ropgadget, seccomp-tools
• OSINT: exifprobe, gdal-bin
• Python CTF sandbox: short Python3 snippets with common CTF libraries installed

Requirements

• Debian or Ubuntu style system with apt
• Internet access for installing packages
• sudo access
• Node.js and npm (installed automatically by setup.sh if missing)

Quick start

Clone the repo and run the setup script:

git clone https://github.com/your-user/mcp-ctf-server.git
cd mcp-ctf-server
chmod +x setup.sh
./setup.sh

After it finishes, you can run the server with:

node dist/index.js

or

npm start

The server speaks MCP over stdio.

MCP client configuration example

For a client that supports MCP configuration similar to Claude Desktop, you can add an entry like this in its config file:

{
  "mcpServers": {
    "mcp-ctf-server": {
      "command": "node",
      "args": ["/absolute/path/to/mcp-ctf-server/dist/index.js"],
      "env": {}
    }
  }
}

Restart the client after editing the config.

Available tools

The server exposes these MCP tools:

• crypto_tools
• disk_forensics_tools
• traffic_forensics_tools
• malware_analysis_tools
• stego_tools
• reverse_engineering_tools
• pwn_tools
• osint_tools
• python_ctf_sandbox

Each category tool accepts:

{
  "tool": "binary-name",
  "args": ["optional", "arguments"],
  "stdin": "optional stdin data",
  "cwd": "/path/to/challenge/files"
}

The Python sandbox accepts:

{
  "code": "print('hello from ctf sandbox')",
  "cwd": "/path/to/challenge/files"
}

Exact wiring of tool calls depends on your MCP client, but the structures above show the shape of the arguments.

Example calls

These examples show how an MCP client might call the tools. The actual format in your client UI may differ, but the arguments are the same.

1. Use rsactftool on a captured key file

Tool name: crypto_tools

Arguments:

{
  "tool": "rsactftool",
  "args": ["--publickey", "public.pem"],
  "cwd": "/home/ctf/challs/rsa-easy"
}

2. Run tshark on a pcap

Tool name: traffic_forensics_tools

Arguments:

{
  "tool": "tshark",
  "args": ["-r", "capture.pcap", "-Y", "http"],
  "cwd": "/home/ctf/challs/web-pcap"
}

3. Scan a binary with radare2

Tool name: malware_analysis_tools

Arguments:

{
  "tool": "radare2",
  "args": ["-A", "suspicious.bin"],
  "cwd": "/home/ctf/challs/malware1"
}

4. Try steghide on a JPEG

Tool name: stego_tools

Arguments:

{
  "tool": "steghide",
  "args": ["extract", "-sf", "hidden.jpg", "-p", ""]
}

5. Use the Python CTF sandbox with pwntools

Tool name: python_ctf_sandbox

Arguments:

{
  "code": "from pwn import *\nprint(cyclic(32))"
}

The server will return combined stdout and stderr from the command or Python snippet.

Safety

This server simply exposes local binaries over MCP. The LLM using it can run these tools with the permissions of the user account that starts the server. Run it only in CTF labs or sandboxes where this is acceptable.

Do not connect it to production systems or networks you do not control.