The image speaks for itself

Aperi'CTF 2019 - Steganography (100 pts).

Aperi’CTF 2019 - The image speaks for itself

Event	Challenge	Category	Points	Solves
Aperi’CTF 2019	The image speaks for itself	Steganography	100	10

Trouvez le flag. Ici c’est relativement simple: l’image par d’elle même.

Challenge: the_image_speaks_for_itself.bmp - md5sum: 52417e96e7ebadbe0959990f35d28714

Open BMP as raw in Audacity an play the sound to have the flag.

In this challenge we got two hints: - The name of the challenge which says “speaks” - The visual content of the BMP file which is a music controller.

The hints converge towards a sound file.

First thing I did was trying to open the BMP file with Audacity (drag and drop). I got the following error:

The error suggests to import the file as raw: “Importer Raw”.

I imported the file as the following: File > Import > Import Raw

The speech is a bit too fast, lets slow it down (Effects > Change speed):

Let’s play it:

Bravo, le flag est APRK{BMP_PCM_POLYGLOT}, le tout en majuscule.

For more information, the challenge has been created using this post.

APRK{BMP_PCM_POLYGLOT}