Debugging Interface⌗

The debugging interfaces challenge on Hack the Box. (link)

Writeup⌗

Using unzip on the .sar, we get two files, a digital-0.bin and meta.json.

Running xxd digital-0.bin | head -1 produces the following output:

00000000: 3c53 414c 4541 453e 0100 0000 6400 0000  <SALEAE>....d...

Not knowing what a <SALEAE> filetype is, I ran a google search and found that Saleae produces logic analysers and some associated software. I downloaded the free Logic-2.3.40-master.AppImage and launched it. I loaded up the .sar file into it and started looking. Visually analysing the waveforms, I found that the serial rate was at 31210 baud, and set the application to view Async Serial at 31210 baud and then set the application to view as terminal data, which presented the flag.