HackTheBox Secure Digital Challenge

Explore the basics of cybersecurity in the Secure Digital Challenge on Hack The Box. This very-easy-level Challenge introduces encryption reversal and file handling concepts in a clear and accessible way, perfect for beginners.

https://app.hackthebox.com/challenges/216

Description

We must retrieve the master key stored on the microSD card that is inside the access control system. The traces connected to the card module are accessible on the top layer of the PCB. This enabled our operative to cut the traces and input a logic capture device in-between them. They could then trigger the read operation of the key that is transmitted over this unprotected serial interface. Can you find out what was read by the microSD card?

Exploitation

Use the Logic2 software to analyze SPI communication with the following default signal mappings:

• MOSI: Channel 01
• MISO: Channel 00
• Clock: Channel 03
• Enable: Channel 02

Export the analyzed data table as a CSV file, and process it using the following command to extract the flag:

cat test.csv | tr ',' ' ' | tr -d '"' | awk '{print $6}' | tr -d '\n' | grep 'HTB'

Summary

The Secure Digital Challenge on Hack The Box introduces the fundamentals of SPI protocol analysis and data extraction. By using tools like Logic2 to analyze SPI communication, you interpret the MOSI, MISO, Clock, and Enable signals. Exporting the captured data as a CSV allows you to process it efficiently with Unix tools such as cat, tr, awk, and grep to extract and identify sensitive information like the HTB flag. This challenge is ideal for beginners, offering hands-on experience with protocol analysis, file handling, and data manipulation.