# mapleCTF 2023

what IS UP chat we're back at it again with another writeup post

last weekend i played [MapleCTF 2023](https://ctf2023.maplebacon.org) with my team
[BLÅHAJ](https://blahaj.awoo.systems) (raised from the dead, i don't remember when the last time i
played as/with BLÅHAJ was but it's been like. a hot second)

there were a couple of interesting challenges in this CTF. BLÅHAJ ended up placing 5th, with a team
of like just a handful of people, which i thought was actually pretty impressive

the challenges we solved that were valued the most points at the end of the CTF were

- flakey ci (misc, 489 points). this was surprising! flakey ci was literally trivial, so i'm
    surprised more people didn't solve it. maybe they were scared of nix. perhaps i had an unfair
    advantage being a nix user.....
- merkle (crypto, 472 points). also surprising! i'm not sure i would classify merkle as a crypto
    challenge, it was more just implementing state recovery of internal data structures using
    probabalistic output. it was not the most time consuming ever to solve, by far
- lost-in-space (pwn, 456 points). still surprising,,, like this was a fairly straightforward
    challenge that required you to implement a graph search algorithm in shellcode with a limited
    amount of program memory/stack. it was interesting, but it wasn't *hard* imo
- AaaS (misc, 436 points). i wasn't involved in solving this one, but it was basically just python
    trivia. a writeup on this wouldn't be very involved
- **coinflip** (misc, 425 points). this one was actually really interesting imo. the discussion on
    this challenge goes into some depth

so basically here's a writeup on coinflip. the writeup is structured in a way to guide you through
the background information required to develop a solution and the thought process involved, so if
you don't rly care about that you can skip to the end with the actual solution script

enjoy~

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- [misc: coinflip](#manipulating-python-rng-using-the-seed-coinflip)
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