Hack the North held a CTF event from September 6-8, 2015 which consisted of hacking puzzles we needed to solve. You can read all about it on my log post at my website.
This repo contains some of the scripts I wrote to solve them.
This contains a Visual Studio .NET project that does a brute-force attack against the listed servers using a list of valid usernames and passwords. It then writes the valid ones it finds to a text file.
This was used to determine which accounts had access to the CTF servers we found.
This script takes in a list of MIDI notes (e.g. C#7, E7), converts them to their hex equivalent, then puts them sequentially into
a target hash string with 'XX' marking locations where these hex values can be put in.
This was used to solve the MIDI puzzle, where an incomplete hash was stored in a MIDI with some notes. Sadly, our MIDI-to-hex mapping was apparently different from the original, so this script produced the wrong hash.
This script is related to the securehash puzzle. The script passes in a string consisting of one character repeated 18 times for each ASCII character into securehash. It then generates a mapping of how each ASCII character can be securehashed depending on its position in the original string. It then guesses the original string based on the provided hash. Due to the way securehash works, it can only "confidently" provide possible guesses for characters 3-14, since the other characters are obscured by securehash's unknown behaviour.
This script is used to identify the 15th character of the original string based on the behaviour of securehash and the clues given to us. This script was used to raise the brute force script's efficiency from O(n^5) to O(n^4) (which brought down the number of possibilities to test from 370 billion to just 4 billion).
Based on the information found through denigma and oneletterguesser, this script brute-forces through 4 billion possible combinations to determine the original string from the given hash. It first goes through alphanumeric ASCII; if that fails, it goes on to the full set. It took about an hour for this script to find the original string.
This was the securehash program provided during the CTF. This is not by me, but my scripts rely on it.
This script was used for the second Hack the North CTF (read about it here). The script reads through the file grid1to26 and decrypts it based on the method described in the CTF Two log post. It then uses NumPy to change the basis of the specified vectors, then uses the changed vectors to find the password from the grid.
The grid that decypher reads and decrypts. This was provided by the CTF admins.