timothy.engineering

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Published on 11/03/2023 20:00 by Tim Sidie

Introduction

I recently participated in a CTF after not having attempted one for a bit. I wanted to brush up on skills related to developing secure web applications. Despite starting late and working into the early morning, I placed in the top 17% of participants, with 1232 total points. I’d like to review my work and maybe could be a resource for future CTF participants.

The Challenges

I finished a number of challenges, titled thusly:

Some I feel like I made significant progress on, but got stuck and shifted to another problem to finish as many as I could. I took the tactic I believe is suggested for students taking the SAT: if a problem is taking too much time, move on and revisit when possible.

YSON

YSON was a challenge using an existing library to exploit a conversion from YAML to JSON. This challenge required a specific escape sequence to, as I would put it, jailbreak out of the process and execute arbitrary commands.

Nine-One-Sixteen

Finders Keepers

Rusty

Jott

Unhackable Andy

Back the Hawks

Repo Recon

Quick Maths

Color Profile

Unhackable Andy II

Written by Tim Sidie

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