Fichier audio étrange

Challenge

J'ai reçu ce fichier audio par un ami. Serait-ce un message caché ?

Attached was this audio file:

343KB

message.wav

Solution

During CTFs, when you need to work with an audio file, know that Audacity is your friend. It really is the reference for editing and tweaking audio.

When I listened to it for the first time, I immediately noticed it was sped up. By clicking on Edit > Audio Clips > Pitch and Speed... I was able to slow it down and lower the pitch.

But I was still not able to make out what was being said so I tried to invert it (Effect > Special > Invert) and reverse it (Effect > Special > Reverse). Then more tweaking by slowing down and lowering the pitch until I could finally make out what was being said: akgmnv0tsw6632a.