NetSpyC2

NetSpyC2 is a Python-based Command & Control (C2) server created for educational purposes, security research, and controlled laboratory environments.
The project demonstrates how encrypted client-server communication, session management, and secure file transfer can be implemented at the application protocol level using Python.

NetSpyC2 does not rely on external TLS stacks. Instead, it implements its own cryptographic handshake and encrypted channel using modern primitives.

Key Features

• Custom TCP-based C2 server
• Application-level handshake validation
• RSA 2048-bit key pair generated at runtime
• RSA-OAEP used for secure AES key exchange
• AES-GCM for authenticated, per-session encryption
• Multiple concurrent client sessions
• Interactive operator console
• Encrypted remote command execution
• Encrypted file upload and download
• SHA-256 integrity verification for file transfers
• Dynamic host and port rebinding
• Persistent logging to file and console

Cryptographic Design

NetSpyC2 establishes secure communication in the following steps:

1. Client connects to the server via TCP.
2. Server sends an identification banner.
3. Client responds with a predefined handshake string.
4. Server sends its RSA public key to the client.
5. Client generates a random AES key and encrypts it using the server’s RSA public key.
6. Server decrypts the AES key using its private RSA key.
7. All further communication uses AES-GCM with a unique nonce per message.

Each connected client maintains its own independent encrypted session.

Requirements

• Python 3.8 or higher
• cryptography Python package
• prompt_toolkit Python package

Install dependencies:

pip install cryptography

pip install prompt_toolkit

Running the Server

Start the C2 server:

python3 NetSpy2.py

Default configuration:

• Host: 0.0.0.0
• Port: 4444

The server generates a fresh RSA key pair at startup.

Operator Console Commands

Available commands in the NetSpyC2 console:

• help – Display the help menu
• list – List all active client sessions
• select <ID> – Interact with a specific client
• info – Display server logs
• rsa keys – Show RSA public and private keys
• set host <HOST> – Change listening host
• set port <PORT> – Change listening port
• banner – Display banner
• exit – Shutdown server

Any unrecognized command is executed locally on the server.

Client Session Commands

Inside a selected session:

• get <file> – Download file from client
• put <file> – Upload file to client
• Any other command is executed remotely on the client

All file transfers are encrypted and verified using SHA-256.

Logging

Logs are written to:

NetSpyC2Server.log

Project Structure

.
├── NetSpy2.py
├── banner.py
├── colores.py
├── NetSpyC2Server.log
└── README.md

Intended Use

This project is intended for educational, research, and controlled lab use only.
Unauthorized use against systems you do not own or have permission to test is prohibited.

License

Creative Commons Attribution–NonCommercial–ShareAlike 4.0 International (CC BY-NC-SA 4.0)

You may modify and redistribute this project for non-commercial purposes only, provided that you preserve this license and give proper attribution.

Disclaimer

This software is provided for educational and research purposes only.
Use only on systems and networks you own or have explicit authorization.

NetSpy