a CTF team from Network Security Lab of National Taiwan University

About Members Awards Contact Writeups CTFtime Twitter



We are planning to hold our first CTF event Balsn CTF in October 2019.

Note that all the information above are subjected to change. Stay tuned!

If you are interested in sponsoring Balsn CTF, feel free to contact us via email!


Balsn is CTF team from Taiwan founded in 2016. Most of our current members are affiliated with Network Security Lab in National Taiwan University. We actively participate in online and onsite CTF competitions. You can browse our recently participated events and rankings on CTFtime. We also publish writeups on CTF challenges.

We are a group of cybersecurity enthusiasts interested in various areas including software security, web security, cryptography, IoT security, and etc. Besides our own research, all of us enjoy playing CTF because we believe it is an excellent chance to hone our skills in practice, catch up with the latest trend, and most importantly – compete and have fun!

In 2018 summer, Balsn attended DEFCON 26 CTF World Final in Las Vegas as a joint team BFS. BFS consists of 4 different CTF teams from Taiwan, including Balsn, BambooFox, DoubleSigma and KerKerYuan. We are so proud to rank 12th place in such a great competition.

Team Members

Active Memebers

Current leader of Balsn. Give me flag (・ω・)
Yet another Shaman King of Balsn. He focuses on all kinds of challenges.
He mainly focus on web, forensics and misc challenges. He’s also in charge of infrastructure tasks when playing attack/defense CTF.
- Blog:
- Twitter: @bookgin_tw
sces60107 (a.k.a Shaman King) knows nothing about reverse engineering and binary exploit, but he knows how to get the flag. This guy specializes in mind-reading and guessing the flag.
Warning: He is a dangerous guy. Everything he touched will malfunction in a jiffy.
I love CTFs, but they don’t like me…
mainly studied in pwn and crypto
A normal student interesting in all hacker things. Now sharpening his skills on web exploitation.
A student who interested in binary analysis and like to PWN everything.
She is a reverse engineer. She reverses what she is interested in and figures out how it does what it does. (especially for Windows OS). Her interests also include Malware Research and Threat Intelligence.
Twitter: @0x000050
A very beginner who interest in pwn and reverse engineering. Now study in NTU-EECS.
struggling with solidity QQ
Pwning my life. (๑•̀ㅂ•́)ﻭ✧
Github: yuawn
If you see a 🌲 walking on the sidewalk.
That’s me. 🙂
My name is Leon Off.

Honorary Members

> “This might be a game, but it isn’t something you play.”
Transfer from pwn to web. Often got a production boost at the last hour of a game.
Solve the challenges ranging from pwn to crypto, from crypto to bruteforce, from butefore to guessing, from guessing to ESP…
is my waifu.
( The challenge I can solve ) ≡ ( The challenge which is too easy )
> “Every challenge is brute-forceable if you believe in yourself.”
For me, 500 500 CAPTCHAs are just an hour of human work.
Welcome to the world of CTF.
A girl studies in computer science and interested in classical music.
She has absolute pitch and used the ability to decode music in D-CTF final. She is now focusing on the area of machine learning.

Selected Awards

DEFCON 26 CTF Final, 12th place (BFS) Las Vegas, USA, Aug. 2018
DEFCON 27 CTF Qualifier, 2nd place (HITCON⚔BFKinesiS) Online, May. 2019
HITCON CTF 2018, 3rd place (BFKinesiS) Online, Oct. 2018
0CTF/TCTF Finals, 2nd place Shanghai, China, Jun. 2019
PlaidCTF 2019, 4th place Online, Apr. 2019
Facebook CTF 2019, 2nd place Online, Jun. 2019
RCTF 2019, 3rd place Online, May. 2019
*CTF 2019, 3rd place Online, Apr. 2019
Teaser CONFidence CTF 2019, 2nd place Online, March 2019
Codegate CTF 2019 Final, 6th place Seoul, Korea, Mar. 2019
HITB-XCTF GSEC CTF 2018 Finals, 5th place Singapore City, Singapore, Sep. 2018
Pwn2Win CTF 2018, 1st place Online, Nov. 2018
Hackover CTF 2018, 2nd place Online, Oct. 2018
ASIS CTF Finals 2018, 5th place Online, Nov. 2018
DefCamp CTF Finals Bucharest, Romania, Nov. 2018
DefCamp CTF Finals Bucharest, Romania, Nov. 2017
Trend Micro CTF 2018 Finals Tokyo, Japan, Dec. 2018
SECCON 2018 Finals Tokyo, Japan, Dec. 2018
SECCON 2017 Finals (1$@AIS3, Balsn) Tokyo, Japan, Feb. 2018


Please contact us at balsn2015 [at] gmail [dot] com. You can write the mail in Chinese, English or Taiwanese.

If you have any question regarding our writeups, please feel free to create an issue in the writeup repository.

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