justCTF [*] 2020

This repo contains sources for justCTF [*] 2020 challenges hosted by justCatTheFish.

TLDR: Run a challenge with ./run.sh (requires Docker/docker-compose and might require sudo as we use nsjail extensively under the hood).

The challenges/ contains challanges directories with the following structure:

• README.md - official challenge description used during CTF
• run.sh - shell script to run the challenge locally (uses Docker and sometimes docker-compose)
• public/ - files that were public/to download
• private/ - sources and other unlisted files
• flag.txt/metadata.json - the flag (don't look there?)
• solv/ - scripts and files with raw solution (used by healthcheck, if exists)
• other files

Challenges

Category	Name	Points	Solves
web	Baby CSP	406	6
web	njs	394	7
web	Computeration Fixed	333	14
web	Go-fs	256	30
web	Computeration	121	103
re	REmap	383	8
re	Rusty	363	10
re	ABNF: grammar is fun	283	23
re	debug_me_if_you_can	279	24
re	reklest	164	70
re	That's not crypto	50	254
pwn	Pinata	474	2
pwn	qmail	363	10
pwn, misc	D0cker	231	38
pwn, misc	MyLittlePwny	50	214
misc, stegano, ppc	Steganography 2.0	500	0
misc, web, re, pwn	PainterHell	500	0
misc	The survey	500	0
misc, web	Forgotten name	72	160
misc	Sanity Check	50	764
fore, misc	Remote Password Manager	347	12
fore, misc	PDF is broken, and so is this file	67	166
crypto	Oracles	383	8
crypto	25519	199	51

Write-ups

Write-ups can be found on CTFTime. You should also look at challenges solution directories, if they exist (solv/).

CTF Platform

We wrote our own CTF platform which is available here.

justCTF [*] 2020 was sponsored by

• Trail of Bits
• Wirtualna Polska