Solutions: The Hex Factor v2009 (Level D200)

It's always a treat when you give hackers a box. It only takes a few moments before they break it down and create a completely new box. You guessed it, D-200 was another of our '09 out of the box challenges. Here we go.

ootb-200.exe looked like yet another binary, but was it ? Your first instinct might have been to reverse engineer it, but you would've wasted your time with that. It told so itself :Ok, no need for debuggers. There must be other ways to find the key to the kingdom ... Did I say key ?

I did. The binary is digitally signed. Let's look into the details then :

And there we have it. Hiding in plain sight. Those familiar with basic math recognize a fibonnaci sequence when they see it. The answer is right there : 55

Do you dare to take on The Hex Factor in 2010? Get your tickets now for BruCON (September, Brussels) or at SANS London (December, London)