San Diego CTF 2024 - Forensic Write Up

k.eii
archive: https://github.com/jonscafe/ctfs-write-ups/tree/main/sandiegoctf-2024

Watch the Waves 1

from the given image, and the hint given by the chall. i think it has something to do with 'WAV'. So what first come to my mind is that the image is a wav file that is converted. So i write a simple script that turned the image into WAV by parsing its pixel value

The result is a wav file with a voice recording of the flag in NATO Phonetic Code sdctf{l3tsg02th3b34ch}

Watch the Waves 2

still on the same topic, but the hint says to scan slowly. i try to convert the png using the same script and got wav that sounds something i familiar with.

with the given hint from the chall description and sound that i familiar with, i notices that it was SSTV recording (Slow-scan television (SSTV), https://en.wikipedia.org/wiki/Slow-scan_television)

so i use SSTV decoder to decode it (i use this https://github.com/colaclanth/sstv) result sdctf{KK6UC_wuz-h3r3}