The FCSC 2020 pre-qualification CTF, organized by the ANSSI cybersecurity team, took place from April 16 to May 4, 2020.
Through 38 challenges, he put to the proof two categories: Junior (15-20 years) and Senior (20-25 years).
The goal was to finish at the top of the ranking in order to be taken to the selections of the team that will represent France during the European Cybersecurity Challenge, in Vienna (Austria) this winter.
The format of this CTF was Jeopardy, and gathered 8 different categories.
This write-up describes the different challenges I managed to solve as well as the path I took, the techniques I used. Most of the challenges that I have solved are not present here, for lack of time to write them.
There are only the simplest ones.
The proposed challenges, written by ANSSI agents who are experts in their fields, were very instructive and made it possible to delve into subjects and vulnerabilities that were little addressed, which adds to the challenge, making it very pleasant to make sometimes despite long hours of head taking (but it would not be a CTF otherwise).
Thank's to the whole ANSSI team for this great edition.
S/o .op_spe