Client-Server Telemetry Demo in C (Educational, Cross-Platform)

🧠 Introduction

This project is now a safe educational exercise to practice C programming with networking and multithreading on Linux and Windows. It keeps a client/server architecture and demonstrates:

• a long-lived TCP connection,
• simple message framing (KEY: and CMD: prefixes),
• a telemetry thread running in parallel with a command listener,
• a small command parser with non-dangerous built-in commands.

⚠️ Disclaimer: this repository is for learning only. Do not use it for unauthorized monitoring or offensive activity.

Features

Client

• 🌐 TCP client connection (connect_to_server).
• 🧵 Background telemetry thread (start_telemetry) that sends a simulated heartbeat.
• 💬 Safe command execution (help, ping, time) without shell execution.
• 🪟 Cross-platform socket lifecycle helpers for Linux and Windows (network_init, network_cleanup, socket_close).

Server

• 📥 Receives KEY: telemetry lines and appends them to keylogger.txt.
• 📄 Receives CMD: command results and appends them to result_commands.txt.
• ⌨️ Lets the operator type commands in stdin and forwards them to the client.

Project structure

Malware/
├── client/
│   ├── include/
│   │   ├── commands.h
│   │   ├── keylogger.h
│   │   └── network.h
│   └── src/
│       ├── main.c
│       ├── network.c
│       ├── keylogger.c      # simulated telemetry thread
│       ├── commands.c        # safe built-in commands only
│       ├── c2_listener.c
│       ├── demon.c
│       └── Makefile
└── server/
    ├── include/
    │   ├── server.h
    │   └── log.h
    ├── src/
    │   ├── main.c
    │   ├── server.c
    │   └── log.c
    └── Makefile

Build

Linux

cd Malware/client/src
make

cd ../../server
make

Windows (MinGW example)

cd Malware/client/src
gcc -Wall -Wextra -I../include main.c network.c keylogger.c commands.c c2_listener.c demon.c -o client.exe -lws2_32

Server uses POSIX APIs in this repo version and is intended to run on Linux.

Usage

1. Start server:

cd Malware/server
./server

2. Start client:

cd Malware/client/src
./client

3. From the server terminal, send commands:

• help
• ping
• time

The server writes outputs to:

• keylogger.txt for telemetry (KEY: messages)
• result_commands.txt for command output (CMD: messages)