You can find the challenge here:  https://backdoor.sdslabs.co/challenges/MUZ It seems that vampire is sharing the flag with a few selected people. This file was caught in between transit from one of…

You can find the challenge here:  https://backdoor.sdslabs.co/challenges/MUZ

It seems that vampire is sharing the flag with a few selected people. This file was caught in between transit from one of his people to the other. See if you can recover the flag from it.

After listening to the audio file you hear an ANNOYING sound, but in the background you can hear a voice telling you something.  So, we need to get rid of the annoying sound and get straight to the point.  We’ll use the process that they use to remove vocals from a track.  We’re going to open up the track in Audacity:

 

skull1

We’re then going to split the track.  This is possible because the track is Stereo.  It would not work with Mono.

skull2

Now, we’re going to select the bottom track which is the “Right” and use the Effect “INVERT”

skull3

Then we’re going to switch both the top and bottom to mono.

skull4

After doing so, you’ll be able to play the track and hear only the vocals.

You know you’ve got it when it starts off “The flag is the SHA256 hash of …”

 

Ashton-Drake, aka GameOfPWNZ, is an information security professional and enthusiast He is the owner of this blog.

6 Comments

  1. i too heard sha 256 of ‘b3gii1d0j2′. i listened to it so many times. i even tried the letters b,t and 3 in place of the ‘d’ in the above string in case i was hearing it wrong. but still it doesnt accept. please help

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