CTFs | 404CTF_2023 | Radio | Avez-vous vu les cascades du hérisson ?

Avez-vous vu les cascades du hérisson ?

In this challenge, we are given a raw audio file. When listening to it, we don’t hear anything… But looking at the spectrogram gives us quite the result:

You may have only yellow stuff and not this beautiful result. If so, when you import your raw data, don’t forget to click on Detect before clicking on Import once your audio is selected.

We don’t see everything, we may use the Zoom to fit feature to see everything. To access this option, you need to left click where the numbers are shown on the left.

Now we have everything:

But this is pretty hard to read. To have a better result I used the following settings for the spectrogram:

You can access those settings by clicking on the arrow, near the name of the audio, then click on spectrogram settings

We can play with the size of the audio and the zoom on it to get this:

We can now see the flag by squinting 404CTF{413X4NDR3_D4N5_UN3_C45C4D35_?}