HITCON writeup - sha1lcode

I participated in Hitcon CTF 2014 late, and didn't take it too serious as I have been busy with other things. The good CTFs always tend to come at the wrong time for me :), or maybe everytime for me is the wrong time. Anyway, we (me and a friend) have…

Private API and lazy programmers

Whenever I get curious about some website or service that provides some kind of an application for a phone Android or Iphone. I get a little bit curious on how did they design their API, how does their application communicate with their services, and so on. What I found out…

Hacker emblem in VGA bios

I wrote a code for VGA 0x13 (256 color) mode which gives us 320x200 64000 bytes at 0xa000:0000 each one of those represent a pixel since this is 256 mode each pixel represent 8bits. Colors are codes from 0-15. We start by initalizing the video mode mov ax, 0x13…

Vortex 12

Continuing the previous post about solving vortex 0-11. I just had some time to solve this one too. level12 Exploit this level knowing that the stack is not executable. You must login to vortex.labs.overthewire.org to complete this level.. So we get the binary and we find. .text…

Entropy analysis

I wanted a tool that does entropy analysis using Shannon entropy, so I wrote one. Shannon is a measure of uncertanity. It is denoted in math as the greek letter Eta, it has an expected value of E[I(X)] where I(X) aka information content is -ln(P(X…

Solving overthewire 0-11

This is going to be a long post or series of posts. I will be solving and documenting each solution of Vortex game at OvertheWire for fun \[^.^]/ Level0 Your goal is to connect to port 5842 on vortex.labs.overthewire.org and read in 4 unsigned integers in host byte…