ECSC 2023


NUS Greyhats recently took part in the European Cybersecurity Challenge @ Norway as a guest team by invitation, since some of us took part in the Asian Cybersecurity Challenge and International Cybersecurity Challenge. I was excited to go as this was one of our first participation as Greyhats in an international CTF. We learnt lots and have fun! I will only include the competition days here as the rest is too long.

Travel Day

Picture is not as good as I thought it would be, but we had a long flight to Norway (~13 hours). The team was tired and cold after our flight, and took a nice rest.

Day 1

This day was meant to be the day when the competition was a Jeopardy-based CTF. It was quite interesting since there were so many challenges, so it was a problem of teamwork and speed.

Day 2

Today was a little different. The CTF was supposed to be in Attack-Defence format, but there were quite a few hiccups on the organizer’s side. It was my first time setting up the infrastructure necessary for this format and I made a few mistakes, sadly.

Day 3

The last day of the competition was Jeopardy-style CTF again. The duration was shorter so the challenges were slightly easier. There were some interesting pwn challenges that I only solved 5 minutes after the CTF ended.


I had lots of fun in the competition, and Norway was a beautiful country to explore and visit. Definitely looking forward to participating next year!

ISITDTU CTF 2022 Finals

I managed to go to Vietnam (specifically Da Nang) for ISITDTU CTF Finals, as part of NUS Greyhats.

It was a wonderful trip, and my second time going overseas with the team.

Day 1!

After changing some money into Vietnamese Dongs, I was a millionaire:

We arrived in Da Nang, and after a short rest, my friend & teammate Vinh brought us to a claypot restaurant:

We toured the night market and visited the Dragon Bridge and Love bridge (didn’t hang anything there though 🙁 ). The Dragon Bridge spits out fire (and water) every Friday:

The Dragon Bridge:

Dragon Spitting Fire:

We visited the beach nearby afterwards since it was closeby. It was pitch black at night.

Beach Afterwards:

Day 2

After breakfast, we went to Linh Ung’s Pagoda, which was situated on an island nearby on top of a mountain.

We visited the 5 peak mountains. Which had incredible a cave system.


We also went to Hoi An:

Day 3

It was competition day. We arrived at the location and participated in the CTF. We were the second foreign team (the other one was bi0s), it was exciting to face off with all the teams. We ended up getting 7th.

There was a dinner by the organizers where we could mingle with the local teams as well, and I spent a lot of time talking with a local team and bi0s as well.

Day 4

We went to Ba Na hills, which were thick with fog:

Day 5

At every restaurant we went to these past few days, I drank this miraculously good tea. Vinh mentioned that it was called Trà Sâm Dứa, and I bought a large pack of it in the morning 🙂

We then left for Singapore.


It was an exciting experience flying overseas for a CTF, and I especially loved Vietnam. I believe the experience will aid in setting up foreign events for Greyhats as well.

Many thanks to the NUS School of Computing for awarding us with the SToW grant, and all the members of NUS Greyhats who contributed to the qualification!

Lake CTF 2022 Finals

NUS Greyhats qualified for LakeCTF 2022 during the recess week. We got to go to EPFL, Switzerland for the finals!


The qualifiers itself was a very thrilling experience. We solved three challenges in the last hour of the CTF – including a challenge that I spent ~18 hours on. I even dropped a module because I didn’t have time to study for the midterm ^~^ (Monday midterms are a tragedy).

Day 1

After a ~13 hour set of flights, we arrived at Geneva. We took a train to Lausanne and checked into our hotel.

The organizers fetched us from the hotel and gave us a tour of EPFL.

Day 2

It was Competition Day! I actually woke up around ~2am since I had to participate in another competition. Nevertheless, after we ate a hearty breakfast, we arrived 5 minutes late. The competition itself was amazing – I did not expect an overseas CTF of this level to be like this. I managed to first-solve both of the binary exploitation challenges – writeups for one of them are here.

We had dinner with the organizers afterwards, where we mingled with other teams. I met up with the challenge author who was surprised (and frustrated) that I solved the challenge the wrong way 🙂

Day 3

After some walking, we ate breakfast:

We also ate some Cheese Fondue.

Day 4

We travelled to various parts of Lausanne:

We walked all the way down to the docks of the lake to get some scenic pictures:

These images are my Desktop wallpaper right now.

Day 5

We travelled to Geneva so that we could visit some places before our flight:


In my opinion, the CTF and travel experience were wonderful. Life in Switzerland felt a lot slower and more relaxing compared to Singapore (though the Cost of Living is a bit high).

I would like to thank the NUS School of Computing for SToW as well as my teammates in NUS Greyhats for making this trip and qualification possible.

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