terjanq

Sourceless writeup by @terjanq

Google CTF 2025

Challenge TL;DR

Players were given a simple puppeteer bot that visits any URL provided by the players. The flag was stored as file:///flag.txt so the goal was to leak this file somehow

Solution

The intended solution was to leak the flag file through an XSSI with help of

Postviewer v5² Writeup by @terjanq

Google CTF 2025

Introduction

Postviewer challenges have become a highlight of the Web category of Google CTF, and this year featured yet another continuation of the series—Postviewer v5². There were two versions of the same challenge; the core challenge was for Chrome, and the other was for Firefox, called Postviewer v5² (FF).

This year, I intended the core challenge to be difficult, and this was indeed the case, given that only two teams managed to retrieve the flag: justCatTheFish and Friendly Maltese Citizens.

Busy Traffic | writeup by @terjanq

justCTF 2025

Challenge TL;DR

The challenge consisted of three components: Traefik v3.4.5 proxy, a Simple Cache plugin for Traefik, and an admin bot that adds a flag to local storage on the challenge domain. The intended solution combined cache poisoning and request splitting to build an arbitrary XSS payload from the available assets.

Solution

Positive Players | Write-up by @terjanq

From justCTF2025

A super secure application generated by the overlords for our positive players. Don't overthink it—it's not too hard—but try to think outside the box!

Vibe coding is the future. Good luck and have fun!

https://g.co/gemini/share/44bdfb8969aa

	<script src="http://localhost:1338/static/safe-frame.js"></script>
	<script src="http://localhost:1338/static/util.js"></script>

	<!-- http://34.44.166.247/exploit-eolldodkgm9 -->
	<script>

	const RELOAD_TIME = 150;
	const SMALL_DELAY = 2;
	const MSG_DELAY = 80;
	const MSG_INTERVAL = 3000;