Writeup to the Brixel winter capture the flag

Contents at a glance

1. Introduction
2. dem challenges
3. An honourable mention
4. Final thoughts
5. Acknowledgements
6. Endnotes

Introduction

After Christmas day, the Brixel winter capture the flag (2020 ed.) commenced. In this CTF, the contestants are presented with fifty-nine (59) different challenges that are organised into nine categories: cryptography, internet¹, stenography, OSINT,² forensics, programming, reverse engineering or cracking, and old tech.

I signed up as the user EntropyThot and started a “team” consisting of myself called the Rocking Philosophers. I rank in the 39th percentile and got a raw score of 75 (see the chart below³). I only solved nine out of the total fifty-nine challenges, but nonetheless would like to discuss some of them and an honourable mention of a fun little challenge that I couldn’t solve, but worth mentioning because it can be used to reference two amazing Twitter users.

The distribution of raw score in Brixel winter CTF (2020 ed.). The vertical line is my place in the contest (check out the scoreboard here, my results here and the code used to generate this graph here).

dem challenges