RingZer0 CTF
Solve hundreds of CTF challenges across many categories
RingZer0 CTF is an online capture the flag site with more than 300 challenges in 15 categories. You pick a challenge, solve it, and submit the flag for points. Some challenges run on live sandboxes that you connect to.
Free · Login needed · Browser · Intermediate
About RingZer0 CTF
It trains a wide mix of skills, from cryptography and forensics to web hacking, reversing and exploitation. After you solve a challenge, you can read other players' write-ups and see different ways to solve it. Approved write-ups earn you gold that you can trade for hints.
You need to register to submit flags. The site is still active and is now hosted by NorthSec. Players with at least 70% of all points can ask for the RingZer0 Certified Elite Hacker title.