Having fun while learning about and pivoting into the world of DFIR.
by ogmini
Continuing with my writeups on my “fails” or the ones I just couldn’t figure out in the timeframe alloted. I want to talk about how I went about trying to solve the challenge and where I went wrong. This should help me in the future by highlighting weaknesses and areas for improvement. Each post will focus on just one “fail” challenge. You can find all my writeups here.
Title: 100X Scale
Description: Decode the secret message
This challenge was under the Cipher section and worth 50 points.
For this solution, I appreciated the writeup from Kevin Pagano at Stark4n6 https://www.stark4n6.com/2025/03/magnet-virtual-summit-2025-ctf-ciphers.html. He makes it sound so easy! Which it is if you have a methodology to follow. Examining the spectrogram shows very definitive frequencies at regularly spaced intervals. Each frequency is a number that represents Hertz and going by the hint of 100X scale, we should divide the frequency by 100. We have a second different encoding obscuring the flag which is ASCII this time. CyberChef using the decimal conversion can convert the numbers to text.