Nullify CTF Team: nullCON

HackIM Web 500

Given the address: http://54.237.107.251/web5/index.php?page=home, find a key.

Immediately we think that it's directory traversal given the page=X in the URL. We attempt various combinations of /etc/passwd, /flag.txt, /key.txt and so on. We look around for a little while and found

on the index.php page. So we try that e.g. ?page=etc/flag and still get an error. Maybe they're checking for single forward slashes? Seems weird but we'll try to double up on the slashes

Pretty easy for a 500 point challenge considering that many people had a ton of issues with the 100 (we never finished it).

Flag: 2f0f7c516d268843341b3d2577ca744a

HackIM Misc. 300

Given an MP3 we are asked to find a key. Normally I just assume that the challenge with MP3 either has multiple tracks or that something that has hidden text.

So I took the track and drop it in Audacity:

We notice immediately that there's a second track...

So we change to spectrogram:

Scroll in...

And we have Morse code. We know that it's morse code given that the longer lines are 3x that of the shorter. So that seems pretty easy for a challenge.. What did we miss? We translate the morse code from left to right and end up with garbage.

We sit around for a little while and figure we just missed something. Maybe it's binary somehow, maybe it's some other representation. After about 15 minutes, someone notices that the actual sound-track (track 1) sounds like it could be backwards. So we read the code from right to left and we get..

.. .-.. --- ...- . --. --- .- -.-.-- -. ..- .-.. .-.. -.-. --- -. ..--- ----- .---- ....- .. ... .- .-- . ... --- -- . -.-.-- -.-.--

Translated..