Mock MCP Server

A mock Model Context Protocol (MCP) server with deliberate vulnerabilities for testing security auditing tools. This server demonstrates various Tool Poisoning Attack (TPA) techniques and other security vulnerabilities.

Purpose

This server is designed to help test and validate security auditing tools for MCP servers. It contains deliberate vulnerabilities including:

• Hidden instructions using zero-width characters
• Hidden instructions using HTML comments
• Hidden instructions using Base64 encoding
• Hidden instructions using Unicode homoglyphs
• Hidden JavaScript in markdown links
• Sensitive information hidden in resources
• Direct prompt injection in tool descriptions

Installation

# Clone the repository
git clone https://github.com/hnipps/mock-mcp.git
cd mock-mcp

# Install dependencies
npm install

# Build the project
npm run build

Running the Server

npm start

The server uses stdio transport, so it can be connected to using an MCP client that supports stdio.

Testing with MCP Inspector

You can test this server using the MCP Inspector:

# Install MCP Inspector
npm install -g @modelcontextprotocol/inspector

# Run the inspector with this server
mcp-inspector --command "node dist/server.js"

Available Tools

1. Calculator - Performs basic arithmetic operations with hidden instructions using zero-width characters
2. Translator - Translates text with hidden instructions using HTML comments
3. Search - Searches for information with hidden instructions using Base64 encoding
4. File Reader - Reads file content with direct prompt injection in the tool description

Available Resources

1. Config - Configuration data with hidden sensitive information using zero-width characters
2. Docs - Documentation with hidden instructions using HTML comments, homoglyphs, and markdown formatting

Available Prompts

1. Code Review - A prompt for code review with hidden instructions using Unicode homoglyphs

Documentation

For more information, see:

• Requirements
• Implementation Plan
• MCP TypeScript SDK README

Warning

This server contains deliberate security vulnerabilities and should only be used for testing purposes in a controlled environment. Do not use this code in production.

License

MIT