404CTF2024

404CTF 2023 is an online CTF event supported by the DGSE (French foreign intelligence service). The challenges where made by students of HackademINT. It was held from April 20, 2024 to May 12, 2024. During this CTF, I played under the name Endurance and scored 9th on the global scoreboard.

The sources for the challenges are available here.

Scoreboard

Challenges

Solved	Name	Points	Tags	Description
	Bébé nageur	100	`Crypto`
	Le petit bain	200	`Crypto`
🩸	Poor Random Number Generator [2/2]	956	`Crypto`	LFSR for random generation
🩸	Poor Random Number Generator [1/2]	271	`Crypto`	LFSR for random generation
	La Seine	968	`Crypto`	Encryption with repeated operations in an euclidean ring
🩸	Zack Adeaux	967	`Crypto`	Encrypted string with a simple backpack problem
	J’éponge donc j’essuie	891	`Crypto`	Sponge construction with small state
	Plongeon Rapide Super Artistique	698	`Crypto`
	SEA - La face cachée de l’Iceberg	999	`Crypto`
	RSAlade-tomatECC-oigNPon	1000	`Crypto`
	La Brasse ou Le Papillon ?	1000	`Crypto`
	Échauffement	100	`Reverse`
	Intronisation du CHAUSSURE	200	`Reverse`
	Revers(ibl)e Engineering [1/2]	703	`Reverse`	Time limited crackme made to be solved with automatic SSE
	Revers(ibl)e Engineering [2/2]	972	`Reverse`	Crackme that downloads code from a server. Made to be solved with automatic SSE
	Bugdroid Fight [1/2]	200	`Reverse`	Find strings spread across an android application
	Bugdroid Fight [2/2]	776	`Reverse`	Crackme on android
	Nanocombattants	956	`Reverse`	Crackme with sub-processes where input bytes can be bruteforced individually
	Poids Raw vs. Cours Jette [2/3]	1000	`Reverse`
	Le Tableau Noir	1000	`Reverse`
	L’entrée du Dojo	1000	`Reverse`
	Jean Pile	820	`Pwn`	simple ret2libc
	Pseudoverflow	100	`Pwn`
	Mordu du 100m	905	`Pwn`	One byte overflow to call a win function
	Antismash	993	`Pwn`
	Vous êtes en RETARD	100	`Web`
	Le match du siècle [1/2]	100	`Web`	Temper cookies
	Le match du siècle [2/2]	200	`Web`	Temper cookies
	Exploit mag	200	`Web`	Bypass paywall using GoogleBot user-agent
	LE GORFOU 42	614	`Web`
	La Boutique Officielle	998	`Web`
	Le tir aux logs	100	`Forensics`
	Darts Bank	200	`Forensics`
	Un boulevard pour pointer	100	`Forensics`	XFS filesystem with a deleted file
	Coup de circuit [1/3]	200	`Forensics`	Find the SHA1 of a malware in logs
	Vaut mieux sécuriser que guérir	741	`Forensics`	Memory dump with persistence using a Windows task
	De bons croissants au beurre	987	`Forensics`
	Poids Raw vs. Cours Jette [1/3]	988	`Forensics`
	Poids Raw vs. Cours Jette [3/3]	1000	`Forensics`
	Serial killer	100	`Hardware`
	Le soulevé de GND	388	`Hardware`	reverse a myHDL circuit
	Comment est votre modulation ? [1/2]	842	`Hardware`	Demodulate ASK signal
	Comment est votre modulation ? [2/2]	942	`Hardware`	Demodulate OFDM signal
	Sea side channel [1/4] - Introduction	946	`Hardware`	Introduction to isogeny-based cryptography
	Sea side channel [2/4] - Reconnaissance	999	`Hardware`	Side channel attack on an isogeny-based system implemented in rust
	Sea side channel [3/4] - Mais où sont les triggers ?	1000	`Hardware`
	Sea side channel [4/4] - Contre-mesures	1000	`Hardware`
	Bienvenue	100	`Misc`	Look for the flag in the rules
	Discord	10	`Misc`	Look for the flag in a discord announcement
	De la friture sur la ligne	100	`Misc`
	Coup de circuit [3/3]	940	`Misc`	Find the sources of a website on GitHub
	Revers(ibl)e Engineering [0/2]	905	`Misc`	Find the shortest equivalent gate circuit using CNOT and Toffoli gates
	L’absence	100	`Steg`
🩸	La Barre Fixe	992	`Steg`	Steganography using x86 prefixes
	Le grand écart	876	`Steg`
	La chute	940	`Steg`	Monoalphabetic substitution cipher
	Du poison [1/2]	100	`AI`	Decrease the accuracy of a federated learning model
	Du poison [2/2]	352	`AI`	Decrease the accuracy of a federated learning model
	Du poison [3/2]	956	`AI`	Change the output of a classifier (based on regression) by modifying 2 weights of the regression model
	Des portes dérobées	891	`AI`	Add a backdoor to a federated learning model
	Des trains superposés	100	`Quantum`
	De l’écoute, pas très discrète	958	`Quantum`	Man-in-the-middle attack on a quantum key exchange
	De l’inversion	995	`Quantum`	Reverse a circuit with quantum gates
	De la multiplicité des problèmes	975	`Quantum`	Prepare a state with a quantum circuit
	Légende	100	`OSINT`	Find information from a picture
	Not on my watch	200	`OSINT`	Find the number of issued watches from a specific model
	Coup de circuit [2/3]	200	`OSINT`	Find the subdomain of a website
	That Escalated Quickly	831	`OSINT`	Find the name of a mountain climber from parts of an image
	Secret training [1/2]	772	`OSINT`	Find a person’s name from a username
	Secret training [2/2]	965	`OSINT`