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Hackfu2015 Challenge 5 - Solution

This is part of my write up from the Hackfu 2015 Security Challenge..

The second challenge I solved was in fact quite easy because I solved a similar one for the SANS Summer challenge in 2014 (where it took me much longer to solve the first time I came across this type of steganography!)

The instructions given were:

  • An audio file to analyse
  • There is a hidden message in it, find it!

  • Below is how I solved that challenge:
  • Listening to the audio file only produces white noise.
  • Looking for strings added to the file does not produce anything.
  • Looking for hidden data using stenography extraction tool such as steghide does not produce anything either.

  • But, If you load the file in a windows software such as Sonic Visualizer, add a layer to show a Spectrogram and playing around with the height and width you can see there are some drawings in the waveform, some dots and dash. This is morse code. Below is an image of a partial screenshot for that data:

    Writing it down as “.” and “-“ gives us:
    "... --- .-.. ...-- --.. -.-- ---.. .--. .-.. ..- .-. .- .-.. --.. -... .-.. ...-- ...— -“

    Using a website to translate morse code such as: THIS ONE
    gives us the following phrase: "sol3zy8pluralzbl33t"

    This is the password to decrypt this challenge file.

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