Rubeus Server

A Model Context Protocol (MCP) server for Kerberos abuse operations using Rubeus on Windows or Impacket on Linux/macOS.

Overview

This MCP server provides comprehensive tools for Kerberos-based security testing, wrapping the functionality of Rubeus (Windows) and Impacket (cross-platform) into a unified interface accessible through the Model Context Protocol.

Security Warning: This tool is intended for authorized security testing only. Unauthorized use against systems you do not own or have permission to test is illegal and unethical.

Features

Ticket Operations

• asktgt - Request Ticket Granting Tickets (TGT) using passwords, hashes, or certificates
• asktgs - Request Service Tickets (TGS) for specific SPNs
• renew - Renew existing TGTs to extend validity
• ptt - Pass-the-ticket to apply tickets to current session
• purge - Remove tickets from logon sessions
• describe - Parse and analyze ticket contents

Roasting Attacks

• kerberoast - Extract service account password hashes via TGS requests
• asreproast - Attack accounts without Kerberos pre-authentication

Ticket Extraction

• dump - Extract all tickets from memory
• triage - Quick summary of available tickets
• klist - Detailed ticket listing
• harvest - Continuously monitor and harvest new TGTs
• monitor - Watch for new TGT events
• tgtdeleg - Extract TGT without elevation using delegation trick

Delegation Abuse

• s4u - Perform S4U2Self/S4U2Proxy constrained delegation attacks
• Bronze Bit exploitation (CVE-2020-17049)

Ticket Forgery

• golden - Forge Golden Tickets with krbtgt hash
• silver - Forge Silver Tickets with service account hash
• diamond - Forge Diamond Tickets (modified legitimate TGT)

Utilities

• hash - Calculate Kerberos password hashes (RC4, AES128, AES256, DES)
• changepw - Change user passwords using TGT
• createnetonly - Create processes with different network credentials
• tgssub - Substitute service names in tickets

Installation

Prerequisites

Windows (Native Rubeus):

• Download Rubeus.exe from GhostPack
• .NET Framework 4.0+

Linux/macOS (Impacket):

pip install impacket

Setup

# Clone the repository
git clone https://github.com/schwarztim/sec-rubeus-mcp.git
cd sec-rubeus-mcp

# Install dependencies
npm install

# Build
npm run build

Configuration

Configure via environment variables:

Variable	Description	Default
RUBEUS_PATH	Path to Rubeus.exe (Windows)	Rubeus.exe
IMPACKET_PATH	Path to impacket scripts	System PATH
RUBEUS_OUTPUT_DIR	Directory for output files	$TMPDIR/rubeus-mcp
RUBEUS_DOMAIN	Default AD domain	None
RUBEUS_DC	Default domain controller	None
RUBEUS_TIMEOUT	Command timeout (ms)	300000
RUBEUS_USE_IMPACKET	Force impacket mode	Auto-detected

Usage with Claude Desktop

Add to your Claude Desktop configuration (claude_desktop_config.json):

{
  "mcpServers": {
    "rubeus": {
      "command": "node",
      "args": ["/path/to/sec-rubeus-mcp/dist/index.js"],
      "env": {
        "RUBEUS_DOMAIN": "corp.example.com",
        "RUBEUS_DC": "dc01.corp.example.com"
      }
    }
  }
}

Usage with Claude Code

Add to your MCP configuration:

{
  "rubeus": {
    "command": "node",
    "args": ["/path/to/sec-rubeus-mcp/dist/index.js"],
    "env": {
      "RUBEUS_DOMAIN": "corp.example.com"
    }
  }
}

Examples

Check Environment

Use rubeus_check_environment to verify your setup

Request a TGT

Use rubeus_asktgt with:
- user: "admin"
- domain: "corp.example.com"
- password: "Password123"

Kerberoasting

Use rubeus_kerberoast with:
- domain: "corp.example.com"
- outfile: "hashes.txt"

AS-REP Roasting

Use rubeus_asreproast with:
- domain: "corp.example.com"
- format: "hashcat"

S4U Delegation Attack

Use rubeus_s4u with:
- user: "svc_account"
- rc4: "<ntlm_hash>"
- impersonateuser: "Administrator"
- msdsspn: "cifs/fileserver.corp.example.com"

Cross-Platform Support

Feature	Windows (Rubeus)	Linux/macOS (Impacket)
asktgt	Full	Full
asktgs	Full	Full
kerberoast	Full	Full
asreproast	Full	Full
s4u	Full	Full
dump	Full	Via secretsdump
Golden/Silver tickets	Full	Limited
Ticket manipulation	Full	Limited

Development

# Watch mode for development
npm run dev

# Build
npm run build

# Run tests
npm test

Security Considerations

• All tools require appropriate authorization before use
• Output files may contain sensitive data (tickets, hashes)
• Credentials are not logged, but ticket data may be captured
• Use in isolated test environments when possible
• Follow responsible disclosure practices

License

MIT License - see LICENSE file for details.

Acknowledgments

• GhostPack/Rubeus - The original Rubeus toolkit by harmj0y
• Impacket - Python classes for network protocols by Fortra
• Model Context Protocol - The MCP specification by Anthropic

Disclaimer

This tool is provided for educational and authorized security testing purposes only. The authors are not responsible for misuse or damage caused by this tool. Always obtain proper authorization before testing systems you do not own.