ZeroDay Alliance
Capture the flag and make our society secure
ZeroDay Alliance CTF is a jeopardy-style competition built on real-world security skills. Work through hands-on challenges in web and binary exploitation, reverse engineering, cryptography, forensics, cloud security and more. Recover each hidden flag, submit it for points, and compete for a place on the live scoreboard.
- Challenges
- Players
- Flags captured
- Points available
Challenges
Discover 14 disciplines
Challenges are grouped by category and rated from Easy to Insane.
Flag format zda{...}
Web Exploitation
Injection, auth bypasses and broken session logic.
Binary Exploitation (Pwn)
Memory corruption, ROP chains and heap tricks.
Reverse Engineering
Pull apart binaries and scripts to recover secrets.
Cryptography
Weak ciphers, bad randomness and protocol flaws.
Forensics
Packet captures, disk images and hidden data.
OSINT / Misc
Open-source intelligence and lateral thinking.
Steganography
Messages hidden in images, audio and file structure.
Mobile Security
Android and iOS apps, APK reversing and insecure storage.
Network Security
Protocols, traffic analysis and misconfigured services.
Hardware / IoT
Firmware, embedded devices, radio and side channels.
Blockchain / Web3
Smart contract bugs, reentrancy and on-chain puzzles.
Cloud Security
Leaky buckets, IAM mistakes and container escapes.
Programming
Scripting and algorithms against the clock.
Mixed
Multi-stage challenges that chain several categories.
Discover how it works
- 1
Create an account
Register as a player and pick a team name for the scoreboard.
- 2
Capture flags
Exploit, reverse and analyse each challenge to recover its zda{...} flag.
- 3
Climb the board
Every correct flag scores points. First solves earn first-blood credit.