My last CTF has come to an end.
I’m very proud that our team, 0x4b52, finished in second place at DEF CON CTF.
On the final day, I was a little upset—not only as a CTF player, but also as a professor. As a professor, I always want to tell my students that we should try to live and compete with integrity. As a CTF player, I deeply respect a community where each of us voluntarily chooses to uphold the spirit of the game. I believe we should hack systems, not the rules.
Of course, I understand that not everyone may see things the same way. And to be fair, I probably didn’t think this way myself when I was younger. Maybe I’ve just gotten a little older and come to believe that this is the way things should be.
Anyway, a huge thank you to BBB for organizing this competition. It is impossible to imagine how much time, effort, and volunteer work it takes to make an event like this possible. If I came across as too aggressive during the game, I’m really sorry. As a team leader, every single tick felt incredibly precious to me.
Congratulations to Blue Water. They definitely outperformed us. Some of the team members are my old friends. I really want to congratulate them.
Most of all, I’m grateful to my teammates and students. It was truly a pleasure playing together.
I had a great time. Thank you, everyone.
Our club will host the first-ever CyKor CTF !
We have prepared a set of high-quality challenges, please play our CTF! 🥹
📢 CyKor CTF (@cykorctf) Announcement
CyKor is pleased to host the upcoming CyKor CTF with great prizes!
• 1st Place: $ 3,000
• 2nd Place: $ 1,500
• 3rd Place: $ 500
The event will be held for 24 hours, from 2025.12.06 01:00 (UTC+0) !
🔗 CTF Link: ctf.cykor.kr
Jinheon Lee retweeted
1. We’re actively looking for sponsors for CyKor CTF.
If you’re interested, please reach out at [email protected] 🚀
2. We’d love to connect with hacking/security clubs from universities abroad!
We’re also considering inviting each other to our universities!! Please DM!! 😁
I posted a DEFCON33 CTF challenge, jxl4fun2 (pwn).
We just shared two new DEFCON 33 CTF two write-ups on our blog!
🛠 Jinheon Lee (KU, 4th year) wrote about jxl4fun2 (pwn)
🧠 Jimin Jeong (KU, 4th year) covered tinii (rev)
Check them out:
🔗 blog.cykor.kr/2025/04/DEFCON…
🔗 blog.cykor.kr/2025/04/DEFCON…
#CTF #DEFCON #DEFCON33 #CyKor
Jinheon Lee retweeted
We have recently launched a blog 🥳🥳
We're proud to share our very first post: "Write-up for AlpacaHack Round 9", written by @ah_p_uh, who is a member of our club!
blog.cykor.kr/2025/02/Write-…
Check it out and keep following our blog for more updates! 🚀
Jinheon Lee retweeted
If you like memory corruption, low-level internals and building custom decompilers to analyse novel exploits check out the write-up here: googleprojectzero.blogspot.c…
Jinheon Lee retweeted
데프콘 본선을 4위로 마무리했습니다.
14명의 한국인이 모여 만든 낭만은 내년에도 계속됩니다. 😆
HypeBoy got 4th place in #DEFCON 🥳
Keep your eyes on 14 koreans :)))
youtu.be/11cta61wi0g
Jinheon Lee retweeted
[Zer0Con2023] "Gold Sponsor"
Thanks to PK Security(@pksecurity_io) for sponsoring the "Gold" 👊
PKSecurity is an offensive research company focusing on OS and Application vulnerability research.
#Zer0Con2023
Jinheon Lee retweeted
Pwn2own 2023 is coming in now. This pwn2own season remind us that we pwned microsoft teams (unfortunately we failed in real round). Here is our first blog post about our journey of pwn2own 2022 microsoft teams RCE.
blog.pksecurity.io/2023/01/1…




















