Tags: audio captcha pattern-matching wav 

Rating: 0

tl;dr:
1. Split input in 10 parts
2. Extract some meaningful byte streams from wav for each letter and put in a lookup table
3. Look for patterns in the captcha to guess

Full writeup: https://github.com/p4-team/ctf/tree/master/2017-11-09-defcamp-final/audio_captcha