34C3 Junior CTF - information_society

The challenge consisted of an audio file

The name was already a hint. The band Information Society released on their 3rd album a hidden track. This track could only be accessed through playing it into a modem.

Upon listening to the sound file it became clear, that it had to be a modem sound, so a program to reverse the data into its original form was required. Intro minimodem. It can be installed in Kali via:

apt-get install minimodem 

The hints from the hidden track proved quite invaluable as 8 data bits and 300 baud were the same values required to resemble this audio file.

minimodem --read 300 -a -8 -f information_society_bonustrack.flac > information_society_bonus

The resulting file was:

file information_society_bonus
information_society_bonus: PNG image data, 657 x 100, 8-bit/color RGBA, non-interlaced