DownUnderCTF 2025 Writeup

CTFTime event link: https://ctftime.org/event/2669

Writeup

• web
  1. sodium

Background

• Starts: 18 July 2025, 09:30 UTC
• Ends: 20 July 2025, 09:30 UTC

DownUnderCTF is the largest online Australia and Aotearoa (NZ) run Capture The Flag (CTF) competition. This CTF aims to up-skill the next generation of Cyber Security Professionals and to grow the CTF community in the AUNZ region. DownUnderCTF is a completely free online event open to all participants around the world. Prize eligibility is restricted to Australian and Aotearoa (NZ) Secondary or Tertiary school students to encourage collaboration and healthy competitive spirit between the nations whilst also promoting cybersecurity skills to students.

With over 4600+ players and 2100+ teams in 2024 from complete beginners to seasoned CTF veterans, our diverse community is strong and we hope you can join us for 2025!

Categories:

• beginner
• pwn
• crypto
• web
• rev
• ai
• osint
• misc

Overview

• Team: ARESx
• Team Solves: 32/64
• Individual Solves: 1/64
• Score: 4744/13683
• Global Rank: 32/1667
• Overall Difficulty To Me: ★★★★★☆☆☆☆☆

What I've learned in this CTF

• web
  1. sodium - SSRF to arbitrary file read, SPILL.TERM HTTP/1.1 request smuggling, and Python format string vulnerability