Challenge Name : Netsec Difficulty : ★★★ Number of solves : 10 This post is in my series of writeup on FCSC 2026, since it’s been long since I did the competition I restarted doing the challenges recently, as well as the 2 I didn’t solve during the competition. Netsec was a 3 Star challenge but there was 4 challenges less solved than this one. You can find the files of the challenge here ...
Challenge Name : Todo Difficulty : ★★ Number of solves : 30 This post is in my series of writeup on FCSC 2026, since it’s been long since I did the competition I restarted doing the challenges recently, as well as the 2 I didn’t solve during the competition. Todo was a 2 Star challenge and the easiest of the 2 star challenges. You can find the files of the challenge here. ...
Challenge Name : History Difficulty : ★ Number of solves : 83 This post is in my series of writeup on FCSC 2026, since it’s been long since I did the competition I restarted doing the challenges recently, as well as the 2 I didn’t solve during the competition. History was a 1Star challenge and the most solved challenge of this year. You can find the files of the challenge here. ...
Challenge Name : Not So Boring Difficulty : ★★★ Number of solves : 7 This post is in my series of writeup on FCSC 2026, since it’s been long since I did the competition I restarted doing the challenges recently, as well as the 2 I didn’t solve during the competition. It was one of the 2 challenges I didn’t had time to solve during the comp. Not So Boring was a 3 Star challenge and the least solved challenge of this year. You can find the files of the challenge here. Note that I changed the local getflag so that it reads the flag.txt in current directory instead of /flag.txt, on the docker-compose.yml it reads the right flag. ...
Challenge Name : Boring Difficulty : ★ Number of solves : 45 This post is in my series of writeup on FCSC 2026, since it’s been long since I did the competition I restarted doing the challenges recently, as well as the 2 I didn’t solve during the competition. Boring was a 1Star challenge and the second most solved challenge of this year. You can find the files of the challenge here. ...
From 3rd april to the 12th april 2026 was the FCSC : the annual competition organised by ANSSI to select members for the ECSC (european cyber competition). I participated in “hors-catégorie”, since I am older than 25. While my objectives starting the CTF was to manage first place in pwn in hors-catégorie, I sadly didn’t perform as I wished and “only” managed to secure the second place and a 45th place overall. ...
This post is part of my training on hackropole, the french website hosting past challenges from FCSC competitions. In this post I will share a writeup for the second 3 Star challenge I did from FCSC 2025. This challenge was the second least solved from this competition. Solving a 3 star challenge shows a very good level (even if big CTFs have eve, harder challenges), so I am quite happy about solving this one. ...
This post is part of my training on hackropole, a french platform that hosts the challenges from the FCSC : an annual competition CTF in France lasting 10 days. The challenges from Hackropole are quite interesting and managing to solve the 3 Stars challenges show really good skills. For my training I focused on the FCSC of this year (2025) and tried to time myself on the challenges to see how long it takes me to do them as a way to evaluate how I’d fare in the real competition. ...
This post is part of my training on hackropole, a french platform that hosts the challenges from the FCSC : an annual competition CTF in France lasting 10 days. The challenges from Hackropole are quite interesting and managing to solve the 3 Stars challenges show really good skills. For my training I focused on the FCSC of this year (2025) and tried to time myself on the challenges to see how long it takes me to do them as a way to evaluate how I’d fare in the real competition. ...
Recently, I started training myself on hackropole, the ANSSI platform that has all the challenges from the past FCSC competitions. So I thought I’d make some writeups for some challenges, here is the writeup for May the Fifth. TLDR lack of boundary check in zForth allow arbitrary read and write use the lack of bounds check to leak PIE address use the PIE address to read got address and gain libc leak overwrite strlen got by system for RCE May the Fifth was a 2 Star challenge from FCSC 2023. A docker-compose.yml is provided so we can test the final exploit on remote. We also had the binary as well as an archive. ...