Challenge Information

CTF Overview

CTF 2023

Date and Time :

10 November 2023, 6:00PM HKT to

12 November 2023, 6:00PM HKT

(The system will operate for 48 hours, participant can access anytime during the contest)

Contest Format :

This is a Jeopardy-style online CTF Contest. Participant will get a score after solving the challenges during the Contest.

Registration Deadline :

The application deadline has been extended from now to 5 November 2023 (Registration after the deadline will not be accepted) 


The final result of the contest will also be published on CTFtime

Learning Outcome Through the Contest

1. Creative thinking

2. Computer security concept, e.g. reverse engineering

3. Networking, e.g, TCP/IP, HTTP

4. Mathematics of cryptography

5. Programming concept and language, e.g. Python, JavaScript, Assembly, Structured Query Language (SQL), HTML

6. Internet search skill

Type of Challenges and Samples
Category Type
Participation Cat


The Contest is divided into 3 categories:

Secondary School

  • For all student of secondary school in Hong Kong

Tertiary Institutions

  • Full-time students in Diploma, Higher Diploma, Associate Degree and Bachelor’s Degree of universities or colleges in Hong Kong

Open Category

  • At least one Hong Kong residents or holders of valid Hong Kong working or study visa in the team

The challenges in the Secondary School category are different from the Tertiary Institution and Open categories. Therefore, if teams of secondary schools want to compete with teams in Open category, they can choose to opt-in the registration form. Please note that in this case, their score will be counted in Open category. For details on how to opt-in, please refer to the instructions in the online registration form. 

The Contest is a team competition, with each team making up of one to four members. Each participant can enrol to only one of the categories and should submit only one entry. Participants shall agree and abide by all the terms and conditions, and rules of the Contest.



Eligible to join

Members are studying in the same secondary school of Hong Kong

– Secondary school, or
– Open (opt-in)

1 of the members is studying in different secondary schools of Hong Kong

– Open

Members are studying Diploma, Higher Diploma, Associate Degree or Bachelor’s Degree in Hong Kong universities or colleges

– Tertiary institutions, or 
– Open

1 of the members is studying master’s or doctoral degree in Hong Kong universities or colleges

– Open

1 of the members is Hong Kong resident, the other 3 members are not

– Open

Oversea Category

  • Team members from outside Hong Kong

Team Name

All the team names will consist of 2 parts (1) Team code; (2) Team name, which would be the name of school/institutions or any self-defined names. The naming convention of each category are shown below

  1. Secondary School
    • Assigned by Organiser
    • Naming convention is {Team Code} – {School name of the members}
    • E.g. S0001 – Tsuen Wan East Secondary School
  1. Tertiary Institution
    • Self-defined name in English with maximum 50 characters, or assigned by Organiser
    • Naming convention is
      • {Team Code} – {self-defined name}, or
      • {Team Code} – {Institution name of each member}
    • E.g. T0001 – HK CTFMan, or T0001 – CUHK, PolyU, AbcdU
  1. Open Category
    • Self-defined name in English with maximum 50 characters
    • Naming convention is {Team Code} – {self-defined name}
    • E.g. O0001 – HK CTFMan

The Organisers reserve the right to change the name of the team at any time without prior notice.

Contest Image

Proof of Answer (Write-up)

The top 5 teams of each category are required to submit the proof of answer (write-up) of 3 solved challenges selected by the Organisers. The Organisers will verify the accuracy while confirming the final ranking.

  • Each team should include maximum of 4 team members (i.e. 1 – 4 members). All team members must fulfil the entry requirements stated in the Eligibility.
  • Representatives of the Contest Organising Committee, members of the project team and supplier(s) of the Contest are not eligible for joining the Contest.
  • The top five teams of each category are required to submit the write-up as specified under the “Write-up” section within the set time by the Organisers.
  • After completing the 48 hours’ Contest, the top three teams of each category with the highest scores and their write-ups confirmed by the Organisers will be declared the gold, silver and bronze winners respectively. In case of a tie in score, the final placing will be decided by time.
  • If any issues occur during the Contest, participants shall report them to the Organisers immediately.
  • Don't attack the CTF platform, such as:
    • Modify the scoreboard;
    • Generate excessive load;
    • Launch denial of service attack;
    • Don't attack any machine or service other than the designated ones.
  • No social engineering attack.
  • Don’t cheat or interrupt the Contest, such as:
    • Share flags;
    • Ask for flags;
    • Delete flags;
    • Intentionally prevent other teams from submitting flags.
  • In the chat room:
    • Don’t send any message which contains violent, obscene or indecent content.
    • Don’t upload any file which infringes any copyrights and intellectual property rights.
  • Do not share any content or details of the CTF challenges with anyone before the end of the contest.
  • Any abuse or violation of the Rules will result in penalty as stated in the Terms and Conditions.
Terms and conditions

General Terms and Conditions

General Terms and Conditions for the Capture The Flag event organised by HKCERT

1. General
  • The participating teams should abide to these Terms and Conditions and the Rules of the Contest. The Organisers reserve the right to penalise team members for noncompliance with suspension of access or disqualification. The related teams and their members shall not raise objection.
  • Each participating team will be named as per the rule specified under the “Team Name” section. The Organisers reserve the right to substitute any name with another name at any time without prior notice. The participants shall not raise objection.
  • The whole team is disqualified if any member of the team is not eligible.
  • All works of the team must be contributed by eligible members of the team.
  • The team should notify the Organisers of any change in team members immediately. The Organisers will verify the identity of the winning team members when confirming their award.
  • The Organisers may allow teams from other countries / regions to compete in the platform. The invited teams would compete in another category. Their score and ranking would not affect the other groups. The participants shall not raise objection.
  • The decisions of the Organisers on the Contest results will be final and the results of the Contest will be published on  The participants shall not raise objection to the Contest results or rankings. 
  • The Organisers reserve the right to substitute any prize with another prize at any time without prior notice.
  • The Organisers reserve the right to amend the Rules from time to time and inform the participants.
Basic Computer Requirement

A computer with web browser

Useful Tools

1. Desktop
Compression utilities
Any Zip tools
File editor
Any text editor
File editor
Any Hex editor
File viewer
Any image viewer
File viewer
Any PDF viewer
Network utilities
Network utilities
Network utilities
Network utilities
Burp suite
Password crack utilities
Any password crack tool
Terminal emulator

2. Online