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.

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

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.

• The incorrectly interpreted command may:

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

• 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.

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

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.

After identifying the layout:

• The device reads WiFi credentials from:

  SD:\DataServer\creds.txt
  

• Connects to the local LAN

• Starts a web server

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

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

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

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

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

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

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

This project explores:

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

No license yet — use at your own risk.