$ ctf -h

Grey Cat The Flag is a CTF hosted by NUS Greyhats in collaboration with National Cybersecurity R&D Labs.

Registration has not opened yet. Stay tuned to our socials to stay updated!

What is CTF?

CTF (Capture The Flag) is a kind of information security competition that challenges you to solve a variety of tasks ranging from a scavenger hunt on wikipedia to basic programming exercises, to hacking your way into a server to steal data. In these challenges, the contestant is usually asked to find a specific piece of text that may be hidden on the server or behind a webpage. This goal is called the flag, hence the name!

If you are new, don’t worry! We will be sharing resources in our Discord server every now and then.

Learn more about CTFs

$ stat ctf

We will host the onsite finals in singapore, to which the top 8 international teams and the top 8 Singapore teams from the qualifiers will be invited.

Each team may send up to 6 people for the finals, and accommodation in Singapore will be provided for the international teams. Accomodation costs for the top 3 international teams will be fully paid for.

A team can be considered a Singapore team only if all its members participating in this CTF event are Singapore Citizens, Permanent Residents (PR), or Long-term Pass holders.

$ stat summit

We are excited to announce that we are hosting our very own Summit this year at Google Everest in Singapore! This event will include talks and workshops on cybersecurity, with plenty of chances to meet new people during breaks and over lunch and tea. Plus, you will have the opportunity to hear from our sponsors as well as concluding with the CTF prize presentation. We hope that you will join us for this fantastic summit!

Event schedule (TBC)

Time (22 June SGT)Event
1000 - 1100Speeches by Gold Sponsors
1100 - 1300Summit talks
1300 - 1400Lunch and networking
1400 - 1600Summit talks
1600 - 1630Tea break
1630 - 1730Keynote speech by Platinum Sponsor
1730 - 1800Prize presentation

$ where ctf

23 March, 9pm (GMT+8) to
24 March, 9pm (GMT+8)
Qualifiers, Online
20 to 21 JuneFinals @ TBC
22 JuneGCTF Summit @ Google Everest (Singapore)

$ man prize

open category

1st placeSGD 6000
2nd placeSGD 3000
3rd placeSGD 1000

local category

1st placeSGD 3000
2nd placeSGD 2000
3rd placeSGD 1000

$ whois sponsors

We would like to extend our heartfelt gratitude to our sponsors .


Join our Discord server if you have more questions.

Q: Is there a team size limit for qualifiers?

A: There is no team size limit for qualifiers. You can have as many team members as you want. However, please note that each team can only send up to 6 members for the finals.

Q: What categories are there?

A: Web, Pwn, Crypto, RE, Blockchain, Misc

Q: Is this CTF beginner friendly?

A: Yes! But we also have hard challenges for the stronger teams.

Q: What's the flag format?

A: grey{...}

$ history

Past Winners


1st placeno rev/pwn no life
2nd placeDiceGang
3rd placeSocial Engineering Experts


1st placecatssg
2nd placenushmellows
3rd placeStranglehold

Past Sponsors

Cyber Security Agency of Singapore
Bakkhos Labs
Ensign InfoSecurity
NUS Computing