A free capture the flag for high schoolers across Australia and internationally.
Outback Overflow is run by high schoolers, for high schoolers, and open to everyone. Play online as a team up to 4 people.
Registration isn't open yet. Join the Discord to hear when it is.
Starts Saturday 21 November, 10:00 AEDT.
Saturday 21 Nov, 10:00 AEDT to Sunday 22 Nov, 10:00 AEDT
At a glance
- When
- Saturday 21 November 2026, 10:00 AEDT, to Sunday 22 November 2026, 10:00 AEDT.
- Where
- Online, hosted on CTFd.
- Who
- Open to everyone. High school teams (verified via official school documents / school confirmation email, will be kept until the event ends) can compete for their own prizes; International participation is also welcomed.
- Cost
- Free.
- Teams
- Up to 4 members.
- Format
- A 24-hour jeopardy CTF. Challenges are released in waves throughout the event.
- Writeups
- Writeups will be published shortly after the CTF challenge ends.
How it works
New to CTFs? In a jeopardy-style event you pick challenges from a board, solve them in any order and score points for your team.
Form a team and register
Registration opens closer to the event on our CTFd instance. Join the Discord to hear when it does, and to find teammates.
Solve challenges
Each challenge hides a flag, which is a short piece of text, often like
oo{Sample_Flag_Do_Not_Use}. Each challenge tells you the exact format to submit.Submit flags and score
Submit the flag on CTFd to earn points for your team. New challenges unlock in waves, so there's always something to come back to.
What you'll solve
Difficulty runs from introductory to advanced, so there's something for every level.
Web exploitation
Find and abuse flaws in websites and web apps.
Cryptography
Break, or properly use, the maths that keeps secrets secret.
Forensics
Dig evidence out of files, disk images and network captures.
Reverse engineering
Work out what a program does without its source code.
Binary exploitation
Find memory bugs in compiled programs and take control of them.
OSINT
Track down answers using publicly available information.
Miscellaneous
Everything that doesn't fit in a box.
Start time where you live
Times are set in AEDT (Sydney, Melbourne, Canberra and Hobart time). Here's what that is across Australia.
| Where | Starts Sat 21 Nov | Ends Sun 22 Nov |
|---|---|---|
| Your device | ||
| UTC | 11:00 pm | 11:00 pm |
| Sydney, Melbourne, Canberra, Hobart | 10:00 am | 10:00 am |
| Adelaide | 9:30 am | 9:30 am |
| Brisbane | 9:00 am | 9:00 am |
| Darwin | 8:30 am | 8:30 am |
| Perth | 7:00 am | 7:00 am |
Prizes
Prizes go to the top performing high school team internationally.
We'll announce the details as sponsors are confirmed.
Registration opens closer to the event.
Sign-ups happen on our CTFd instance. Join the Discord to be told when registration opens, ask an organiser a question and find teammates.
Who's behind it
Outback Overflow is the first event from the High School Cybersecurity Community, a student-run group for high schoolers across Australia. We're building the challenges with support from university security societies including UNSW SecSoc, UTS Cybersecurity Society, and more.
Want to write a challenge or back the event? Read about sponsoring Outback Overflow or email [email protected].