DataServer

Experimental Project

DataServer is a side project built for the M5 Cardputer (ESP32). It acts as a USB device that connects to a Windows machine, gathers system information, and hosts that data on a local web server.

This project was created out of curiosity and experimentation with USB HID injection, serial communication, and embedded web servers.

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Overview

DataServer works by:

1. Emulating a USB keyboard (Rubber Ducky-style)
2. Injecting Base64-encoded PowerShell commands
3. Collecting system data from the target machine
4. Sending the data back via serial (8N1 over USB)
5. Hosting the collected data on a local web interface

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⚠️ Keyboard Layout Injection Warning

During the keyboard layout and COM port detection phase, DataServer intentionally sends two different command variants:

• One for QWERTZ (German layout)
• One for QWERTY (US layout)

Because only one layout can be correct, at least one of these commands will be interpreted incorrectly, resulting in gibberish input on the target system.

Potential Risk

• The incorrectly interpreted command may:

  • Execute unintended commands
  • Produce unpredictable behavior
  • Interact with the system in unexpected ways

Safety Note

• This behavior has been tested with:

  • German QWERTZ
  • US QWERTY

In these cases, the incorrect command does not result in harmful or destructive actions.

However:

There is NO guarantee of safety on other keyboard layouts or system configurations.

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How It Works

1. COM Port Discovery

To communicate over serial, the device first needs to identify its COM port on the host machine.

• On startup, the ESP32:

  • Listens for 5 seconds for incoming serial data

• If nothing is received:

  • Injects a qwertz and qwerty version of a PowerShell command
  • Enters deep sleep for 9 seconds (disconnects from USB)

During this time:

• PowerShell:

  • Takes a snapshot of available COM ports

• After reconnect:

  • Takes another snapshot
  • Compares both lists
  • Identifies the new COM port
  • Sends the port name (e.g. "COM5") back to the device

On reboot:

• The ESP32 simply listens again and receives the COM port string

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2. Keyboard Layout Detection

Because keystroke injection depends on the keyboard layout, the device injects a command that returns the layout in plain text.

• The device sends:

  • A QWERTZ version of the command
  • A QWERTY version of the command

• The working command responds with:

  • "qwertz" or "qwerty"

This determines how future commands are injected.

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3. Network Setup

After identifying the layout:

• The device reads WiFi credentials from:

  SD:\DataServer\creds.txt
  

• Connects to the local LAN

• Starts a web server

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4. Data Collection

When the user presses "Refresh" on the web interface:

• The ESP32:

  • Opens PowerShell via injection
  • Executes a large Base64-encoded command

• The Windows machine:

  • Collects system information
  • Sends it back via serial (8N1)

• The ESP32:

  • Receives and displays the data on the website

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5. Access Point Mode

If you press G0 within 5 seconds after keyboard layout detection:

• The device:

  • Reads credentials from creds.txt
  • Starts its own WiFi network
  • Hosts the web interface locally

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Web Interface

• Hosted directly from the ESP32
• HTML files are stored on the SD card

Preview

Features

• 🔄 Refresh button → triggers data collection
• 🔁 Restart button → restarts the ESP32

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File Structure on the ESP32

SD:\
└── DataServer\
	├── creds.txt        # WiFi credentials
	└── index.html       # Web interface

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Disclaimer

This project uses USB HID injection (Rubber Ducky behavior).

• Intended for educational and experimental purposes only
• Do not use on systems without permission

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Why This Exists

This project explores:

• USB HID device emulation
• Serial communication over USB
• PowerShell automation
• Embedded web servers on ESP32

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License

No license yet — use at your own risk.