Need some help?

Are you stuck? No worries, we've written down some info on this page. Still stuck after reading this help page? Do not worry, we are here to learn, not to be a pain in the ass. Ask around in the Space Leiden #ctf Discord channel, but please do not spoil the fun for others!

What is a CTF?

A CTF is a Capture The Flag. We recommend you watch this video if you are new to CTFs:

Who is this CTF for?

This CTF is for everyone! That's why most challenges will be relatively easy for more experienced CTF participants. No worries though: a lot of challenges have harder follow-up challenges.

Who is The Space Leiden?

The Space Leiden is a hackerspace and makerspace based in Leiden, which is a city in the Netherlands. Interested in more? Check out our website!

What does a flag look like?

Every challenge has a flag to prove you solved it. Most flags are formatted like the following:


Knowledge challenges however do not use this format. Knowledge flags are usually not case sensitive, other flags are case-sensitive.

How does it work?

Each day, a knowledge challenge and a large challenge will be released. This year, all challenges are prefixed with a number. There is somewhat of a story, so if you want to follow that story it's wise to do the challenges in order.

What do I need to solve challenge X?

Every challenge is divided into a category. Every category requires a different set of tools and knowledge.

We recommend the following resources for information on some security-related CTF challenges:

  1. CTF 101:
  2. Trail of Bits CTF guide:
  3. Installing Linux in VirtualBox:
  4. The swiss army knife for manipulating text input: