DownUnderCTF-Tim Tams(Misc)

Misc challenges are usually random and require logic and lots of patience to solve. Surprisingly this one wasn’t too challenging.

The challenge description is as follows

We are given a really noisy wav audio file, I had no clue of solving this at first when my regular audio steganography tools failed. But my teammate came into play with a really good suggestion. QSSTV!

https://storage.googleapis.com/files.duc.tf/uploads/Clive.wav

QSSTV is a utility for dealing with slow scan television signals. From the challenge description, we can pick out a hint “When I eat too many Tim Tams, I get rather slow!”.

I used the following commands to setup qsstv on linux sudo apt-get install pavucontrol sudo apt-get install qsstv

We need the pavucontrol utility to be able to open audio files.

Type qsstv on the terminal to open the program and select the audio file you’re going to work with

qsstv maps the wav audio into an image and we can see at the top left what appears to be an encoded flag.

QHGPS{UHZOYR_Z3Z3_1BEQ}

This is ROT13, we decode the flag to: DUTCF{HUMBLE_M3M3_1ORD}

Happy hacking :)