Swag Bag Challenge

Swag Bag Lab 2 Challenge


Using the information and tools learned from Swag Bag Lab 2, you will capture, decode and decipher OTA 433 MHz signals. It is strongly suggested that you complete the Swag Bag Lab 2 before attempting to engage this challenge. 

Setup (How to install the special binary file)

Start by downloading the bonus challenge binary file here: https://wwhfbaglab.s3.amazonaws.com/SBL2-Challenge.ino.esp32.bin

If not already connected, please connect the ESP32 Transmitter board to the PC hosting the Arduino IDE. Open the Arduino IDE and click File-New.

Copy and paste the following sketch over the sample text in the sketch window and save the sketch as ‘test_sketch’.

void setup() { 


 void loop() { 
  Serial.println(“TEST SKETCH”); 


The purpose of this sketch is to find the location of the ‘upload’ build folder on your personal PC, to be used later to install our specially prepared SBL2-Challenge binary file. The location of this command line can vary from system to system, and this procedure will provide the required path. 

The test_sketch.ino is a simple app that will display ‘TEST SKETCH’ once every second on the serial monitor. 

Before we upload the sketch, we need to enable ‘upload verbose output’. Click File-Preferences and check the Upload box for ‘Show verbose output during:’. Click OK 

Click the right-arrow (shortcut for click Sketch-Upload) 

Examining the verbose output of the Upload process, find the command line that we are interested in. It will be the last line displayed before the red text output..


Open a text editor, copy and paste the command line to the editor. Examine the command line to determine the path to your test_sketch build folder. Also, find the ‘test_sketch.ino.binreference in the command line.

Copy the download binary file ‘SBL2-Challenge.ino.esp32.bin’ to the build folder specified in the command line path for your specific system.


Now, edit the command line and replace the occurrence of ‘test_sketch.ino’ with ‘SBL2-Challenge.ino.esp32.bin’. 


Open a terminal and navigate to the build folder. Copy the modified command line in its entirety, paste it in the terminal and press ENTER. The binary file will then be uploaded to the ESP32 Transmitter board (overwriting the previous application) and program execution will begin. 

The challenge

The ESP32 Transmitter board has now been programmed to transmit a sequence of encoded (binary) data values in an endless loop. The objective of this challenge is to capture, decode and decipher the meaning of these values using the tools and information obtained from performing the Swag Bag Lab 2 hardware lab. 

Helpful hints:

  • Hashcat
  • Crack the hash
  • No leetspeak
  • No special characters
  • Less than 10 characters in length