EvilLimiter Server

A Model Context Protocol (MCP) server that provides controlled access to EvilLimiter network bandwidth management and monitoring capabilities.

IMPORTANT LEGAL NOTICE

This tool performs ARP spoofing and traffic manipulation. It must ONLY be used on:

• Networks you own
• Networks where you have explicit written permission to perform testing
• Isolated lab environments for educational purposes

Unauthorized use may violate computer fraud laws, network policies, and regulations. You are solely responsible for ensuring legal compliance.

Purpose

This MCP server provides a secure API interface for AI assistants to control network bandwidth, monitor traffic, and manage device connections using EvilLimiter. Designed for authorized network testing, debugging, and educational purposes only.

Features

Current Implementation

• scan_network - Scan for online hosts with optional IP range specification
• list_hosts - Display all discovered hosts with IDs and network information
• limit_bandwidth - Throttle bandwidth for specific hosts (upload/download/both)
• block_host - Block internet access for specific hosts
• free_host - Remove all restrictions from hosts
• add_host - Manually add hosts to the management list
• monitor_bandwidth - Real-time bandwidth usage monitoring
• analyze_traffic - Analyze traffic patterns without limiting
• watch_status - View watchlist for reconnection detection
• watch_add - Add hosts to reconnection watchlist
• watch_remove - Remove hosts from watchlist
• watch_configure - Configure watch settings (range, interval)
• flush_configuration - Reset all network configurations

Prerequisites

• Docker Desktop with MCP Toolkit enabled
• Docker MCP CLI plugin (docker mcp command)
• Linux host (EvilLimiter requires Linux)
• Network interface access (container needs NET_ADMIN and NET_RAW capabilities)

Installation

1. Build Docker Image

docker build -t evillimiter-mcp-server .

2. Create Custom Catalog

Create ~/.docker/mcp/catalogs/custom.yaml:

version: 2
name: custom
displayName: Custom MCP Servers
registry:
  evillimiter:
    description: "Network bandwidth control and monitoring via EvilLimiter"
    title: "EvilLimiter"
    type: server
    dateAdded: "2025-01-29T00:00:00Z"
    image: evillimiter-mcp-server:latest
    ref: ""
    tools:
      - name: scan_network
      - name: list_hosts
      - name: limit_bandwidth
      - name: block_host
      - name: free_host
      - name: add_host
      - name: monitor_bandwidth
      - name: analyze_traffic
      - name: watch_status
      - name: watch_add
      - name: watch_remove
      - name: watch_configure
      - name: flush_configuration
    metadata:
      category: monitoring
      tags:
        - network
        - bandwidth
        - monitoring
        - security
      license: MIT
      owner: local
    containerConfig:
      capAdd:
        - NET_ADMIN
        - NET_RAW
      network: host

3. Update Registry

Edit ~/.docker/mcp/registry.yaml and add under registry::

evillimiter:
  ref: ""

4. Configure Claude Desktop

Add "--catalog=/mcp/catalogs/custom.yaml" to your Claude Desktop config args.

5. Restart Claude Desktop

Container Privileges

This container requires elevated network privileges to function:

docker run --cap-add=NET_ADMIN --cap-add=NET_RAW --network=host evillimiter-mcp-server

Or use --privileged flag (less secure but simpler).

Usage Examples

In Claude Desktop, you can ask:

• "Scan the network for all devices"
• "List all connected hosts on the network"
• "Limit device ID 3 to 100kbit bandwidth"
• "Block internet access for device IDs 2 and 4"
• "Monitor current bandwidth usage of limited devices"
• "Analyze traffic for device ID 5 for 60 seconds"
• "Add device 192.168.1.100 to the watchlist"
• "Free all restrictions from device ID 6"
• "Show the current watch status"
• "Flush all network configurations"

Environment Variables

• EVILLIMITER_INTERFACE - Network interface to use (auto-detected if not set)
• EVILLIMITER_GATEWAY_IP - Gateway IP address (auto-detected if not set)
• EVILLIMITER_GATEWAY_MAC - Gateway MAC address (auto-detected if not set)
• EVILLIMITER_NETMASK - Network mask (auto-detected if not set)
• EVILLIMITER_SAFETY_MODE - Enable safety checks (default: true)
• EVILLIMITER_ALLOWED_RANGES - Comma-separated IP ranges to allow (if safety mode on)
• EVILLIMITER_API_TOKEN - API token for authentication (optional)

Architecture

Claude Desktop → MCP Gateway → EvilLimiter MCP Server → EvilLimiter CLI
                                         ↓
                              Network Interface (ARP/iptables/tc)
                                         ↓
                                 Docker Secrets (optional)

Development

Local Testing

# Set environment variables for testing
export EVILLIMITER_INTERFACE="eth0"
export EVILLIMITER_SAFETY_MODE="true"
export EVILLIMITER_ALLOWED_RANGES="192.168.1.0/24"

# Run directly (requires root/sudo)
sudo python evillimiter_server.py

# Test MCP protocol
echo '{"jsonrpc":"2.0","method":"tools/list","id":1}' | sudo python evillimiter_server.py

Adding New Tools

1. Add the function to evillimiter_server.py
2. Decorate with @mcp.tool()
3. Update the catalog entry with the new tool name
4. Rebuild the Docker image

Troubleshooting

Tools Not Appearing

• Verify Docker image built successfully
• Check catalog and registry files syntax
• Ensure Claude Desktop config includes custom catalog
• Restart Claude Desktop completely

Permission Errors

• Ensure container runs with proper capabilities
• Check if running with --network=host
• Verify iptables/tc access

Network Detection Issues

• Manually specify interface with EVILLIMITER_INTERFACE
• Set gateway IP/MAC if auto-detection fails
• Check container network mode

Security Considerations

• Container requires elevated privileges (NET_ADMIN, NET_RAW)
• ARP spoofing affects entire network segment
• All actions are logged to stderr
• Safety mode restricts target IP ranges
• API token authentication available
• Input sanitization prevents command injection
• Never expose this service to the internet

Limitations

• IPv4 only (ARP spoofing requires IPv4)
• Linux host required
• Affects all devices on local network segment
• Cannot bypass HTTPS certificate pinning
• Detection possible via ARP monitoring tools

License

MIT License - Use at your own risk and responsibility