Through the organization of the annual Catch competition, we endorse the ideas of the Cyber Security Month in 2022, thus contributing to building a more secure Internet environment and cyberspace. The competition is organised by the CESNET Association.


  • 2022-11-14 12:28 The write-up winners were published.
  • 2022-11-14 13:23 The received write-ups were published.
  • 2022-10-31 12:19 The Top 30 awards winners were published.
  • 2022-10-25 12:45 Number of players rewarded with smaller gitfs was increased from 20 to 30.
  • 2022-10-16 19:52 The challenge Orderly IS was restarted (if you had problem to solve this challenge, try it now again).
  • 2022-10-12 13:39 The challenge Blog site was restarted (all registrations and posts were also removed by this step).
  • 2022-10-11 09:47 The first blood awards were evaluated and published.
  • 2022-10-10 12:32 Most of webs related to challenges uses just http (not https), if the web is not accessible, the problem is related to cached HSTS for subdomains of in your browser (HSTS header settings was changed few weeks ago).

Basic Information

  • The Catch is intended as an individual competition, but teamwork is not prohibited.
  • The registration into the CTF portal will be opened along with the start of the competition on Monday 10 October 2022 at 12:00 CEST.
  • The competition will be closed on Monday 31 October 2022 at 12:00 (CET).
  • The top 20 players will be invited to Award ceremony (can be changed to on-line ceremony if necessary).
  • Best contestants will receive valuable prizes. Other prizes (T-shirts, hoodies, small presents) will be awarded (see The Rewards).
  • For more information, see the Competition rules, Frequently asked questions and Personal Data Protection.

Competition Rules Frequently Asked Questions Personal Data Protection

The Rewards


voucher worth
CZK 8,000


voucher worth
CZK 6,000

3rd – 5th

voucher worth
CZK 3,000

6th – 30th

smaller gifts (i.e. board games, t-shirts, sweatshirts)

Extra rewards:
  • Speed premium – the first solution of each challenge will be rewarded by small CESNET presents. Each player can win this premium award only once.
  • Write-upsbest write-ups will be rewarded with smaller gifts (i.e. board games, t-shirts, sweatshirts, etc.)

Only individuals will be awarded.

How to join the Competition

  1. Please read the Competition rules and/or FAQ.
  2. Register yourself once the registration is open, i.e. create a player account in the CTF platform (nickname, e-mail and password need to be filled in).
  3. Start solving the challenges:
    • Choose any of the challenges from the list. The challenges have some prerequisites, which has to be met before the challenge is accessible. Visible challenges can be solved in whatever order.
    • Read the challenge assignment carefully.
    • Download the file(s) for the analysis or visit the stated URL.
    • Perform the analysis (when correctly performed, you should be able to discover the flag in format FLAG{xxxx-xxxx-xxxx-xxxx} or flag{xxxx-xxxx-xxxx-xxxx}).
    • Insert the flag into the platform (to verify its correctness and acquire the points). The number of attempts is limited (the flag should be acquired by analysis not guessed).

Register and join!


The organizational team is available at e-mail address