Cheap Rubber Ducky Digispark Attiny85

^{on Aug. 26, 2023, 1:49 a.m.}

This install guide assumes you are running Ubuntu 22.04 on bare metal.

First, we have to install some prerequisites:

sudo apt install libusb-dev arduino arduino-core arduino-mk

Next, setup the user account to allow the dailout:

sudo chmod a+rw /dev/ttyACM0
sudo usermod -a -G dialout $USER

Next, disable brltty to keep it from interfering:

sudo systemctl stop brltty-udev.service
sudo systemctl mask brltty-udev.service
sudo systemctl stop brltty.service
sudo systemctl disable brltty.service

Next, update udev rules to not cause issues:

sudo nano /etc/udev/rules.d/49-micronucleus.rules

# UDEV Rules for Micronucleus boards including the Digispark.
# This file must be placed at:
#
# /etc/udev/rules.d/49-micronucleus.rules (preferred location)
# or
# /lib/udev/rules.d/49-micronucleus.rules (req'd on some broken systems)
#
# After this file is copied, physically unplug and reconnect the board.
#
SUBSYSTEMS=="usb", ATTRS{idVendor}=="16d0", ATTRS{idProduct}=="0753", MODE:="0666"
KERNEL=="ttyACM*", ATTRS{idVendor}=="16d0", ATTRS{idProduct}=="0753", MODE:="0666", ENV{ID_MM_DEVICE_IGNORE}="1"
#
# If you share your linux system with other users, or just don't like the
# idea of write permission for everybody, you can replace MODE:="0666" with
# OWNER:="yourusername" to create the device owned by you, or with
# GROUP:="somegroupname" and mange access using standard unix groups.

Reload the udev rules:

sudo udevadm control --reload-rules

Next, run Arduino IDE with sudo and go to File menu, and select Preferences. Then in the Additional Boards Manager Urls, put this link:
sudo arduino
http://digistump.com/package_digistump_index.json

Next, go to Tools menu, then the Boards submenu, select Board Manager. In the Type field, digi and install Digistump AVR Boards.

Next, install micronucleus and replace the version that is installed with Digistump AVR Boards so you don't have errors later:

git clone https://github.com/micronucleus/micronucleus.git
cd micronucleus/commandline
make
sudo make install
sudo su -
cd ~/.arduino15/packages/digistump/tools/micronucleus/2.0a4/
mv micronucleus micronucleus.original
cp /usr/local/bin/micronucleus .
exit

Next, plug in a fresh Attiny85 and let's flash it with the latest micronucleus t85 firmware to avoid issues with a flash

cd ~/micronucleus/ # or whereever you cloned the folder
sudo micronucleus --run firmware/upgrades/upgrade-t85_default.hex

Next, go to Tools menu, then Boards submenu, Click Digistump AVR Board and select Digispark (Default — 16.5mhz).

Then, copy/paste the code below to make sure everything is working:

#include "DigiKeyboard.h"

void setup() {
// don't need to set anything up to use DigiKeyboard
}

void loop() {
DigiKeyboard.sendKeyStroke(0);
DigiKeyboard.println("Haxored!");
DigiKeyboard.delay(5000);
}

Next, click verify and upload next. Done. Happy haxoring! Open a notepad, and plug in the USB. If it types the word, "Haxored" it worked.

References:

http://digistump.com/wiki/digispark/tutorials/connecting
https://infosecwriteups.com/make-usb-rubber-ducky-with-less-than-3-fa72dac9e4de
https://www.amazon.com/gp/product/B0836WXQQR/
https://koen.vervloesem.eu/blog/how-to-upgrade-the-micronucleus-bootloader-on-the-digispark/