Bigorneau

Description

We often try to obtain shellcodes with strange constraints, either in size, alphanumeric, etc. Here, we’re attempting a new weird constraint for an x64 shellcode: you are only allowed to use 6 different byte values (i.e., len(set(shellcode)) <= 6)!

Files

docker-compose.yml
bigorneau
15.80 KiB – 344174c0cf6684994ea7a95d5eda0df7c5c04175f8b6915b4b240c2a0f4e696c
bigorneau.c
405 B – 784c31123b3ee2980b74d28fc4fb8d687688a016d07faab0dc952a795def8760
bigorneau.py
1.23 KiB – cd425fc8d98d1532aa66b46dc373c4bc205c665482ce910fc006ff5946554743

Authors

Cryptanalyse

XeR

Challenge Instructions

First, download docker-compose.yml:
curl https://hackropole.fr/challenges/fcsc2025-pwn-bigorneau/docker-compose.public.yml -o docker-compose.yml
Launch the challenge by executing in the same folder:
docker compose up
Then, in another console, access the challenge with Netcat:
nc localhost 4000

⚠️ Important: You must solve the challenge by interacting with the Docker container through the exposed network port. Any other way is not considered valid.

In case you encounter problems, please consult the FAQ.

Flag

You don't have JavaScript actived. No problem! You can check your flag like this: echo -n 'PUT_THE_FLAG_HERE' | sha256sum # possible output: 96a8029184c815cb219c7a614ea5f0fb096bf13859b395885f0aa065d7ca0147

Writeups

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Date	Author	Language	Tags
2025-04-28	tritrilemagnifique	🇫🇷