Stealth Chat

Stealth Chat is a secure chat application that uses simple ROT encryption to obfuscate messages and hides communication within ICMP packets. This project uses a combination of Python, Bash, and third-party tools to ensure both secure and stealth communication between clients and servers.

Features

• Stealth communication: Hides chat messages in ICMP packets.
• Encryption: Uses a simple ROT cipher to encrypt messages.
• Cross-platform: Supports both Linux and Windows with the help of ptunnel.
• Port forwarding: Ensures secure communication through port forwarding.
• Bash and Python scripts: Automates setup and connection handling.

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Project Structure

.
├── README.md
├── include
│   ├── client-connect.sh
│   ├── line-formatter.sh
│   ├── messenger.sh
│   └── server-connect.sh
├── main-chat.sh
├── pf-lin.py
└── pf-win.py

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ICMP Packet Structure

2 Machine Data Flow Model

NOTE:

For the sake of simplicity, this project has been modified to chat on loopback address instead of two machines. Users have to run this software within their respective OS, no need to chat inter-OSs. Route the traffic through ports such that, the data gets encrypted, burried in packets and then decrypted approriately.

Dependencies

• ptunnel-ng: A tool to setup ICMP tunnel on WSL
• ptunnel: A tool to setup ICMP tunnel on MAC (ng version is not available on homebrew)
• Python 3: Required for port forwarding.
• ncat: Netcat tool that comes with nmap

Installation (Acc to your OS)

A. Install ptunnel-ng on WSL or Linux

Clone and build ptunnel-ng from the following repository:

git clone https://github.com/utoni/ptunnel-ng.git
cd ptunnel-ng
chmod +x autogen.sh
./autogen.sh
make install

OR

curl http://ports.ubuntu.com/pool/universe/p/ptunnel-ng/ptunnel-ng_1.42-1_arm64.deb -o ptunnel-ng.deb

sudo dpkg -i ptunnel-ng.deb

B. Install ptunnel-ng on Mac

brew install ptunnel

Usage

Step 1: Start ptunnel listner

On WSL
sudo ptunnel-ng
On MAC OS
sudo ptunnel

Step 2: Connect ptunnel to listener

On WSL
sudo ptunnel-ng -p127.0.0.1 -l6666 -R5555
On Mac OS
sudo ptunnel -p 127.0.0.1 -lp 6666 -dp 5555 -c lo0

Step 3: Start Secure Tunnel 2

Start port forwarder 2

python3 pf-lin.py

Step 4: Start Secure Tunnel 1

Start port forwarder 1

python3 pf-win.py

Step 5: Start the Chat Server

Run the main Bash script to start the chat server

chmod +x main-chat.sh
./main-chat.sh

Step 6: Connect to the Chat Server

Use ncat to connect to the chat server through the secure tunnel:

ncat 127.0.0.1 4444

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If you observe the traffic between 6666 and 5555 on your machine (In implementation of 2 machines, the space between port 6666 and 5555 should be the Internet) with Wireshark, you will notice that all communication takes place over ICMP and the data within the packet is encrypted as expected