Nikola Winata
CTF competitor, systems security enthusiast, and web developer · Singapore
I write down challenge analysis, exploit development, and the details I want to remember later. I focus on binary exploitation, reverse engineering, and security-oriented development with C, C++, and Python.
Archive
Writeups
-
National Cybersecurity Olympiad 2026
Writeups for the pwn challenges that I solved (which is all of them eventually)
Around two weeks ago, I participated in the National Cybersecurity Olympiad (NCO) 2026 qualifications and finals, where for the first time I not only had to do pwn, but also actual
-
YBNCTF 2025
Writeups for the pwn challenges I wrote
YBNCTF 2025 was a CTF competition hosted by the Yes But No team, for which I contributed five pwn challenges:
-
BlahajCTF 2025 Finals
Writeup for the pwn challenge 'ret2...what?' by @FS in the BlahajCTF 2025 Finals
This weekend, I participated in the BlahajCTF 2025 Finals. There were three pwn challengesin which I only solved one. ‘ret2…what’ by @baaaa_fs7 (FS) was a challenge I came close to
-
BlahajCTF 2025
Writeup for the pwn challenge fastnotes by FS in BlahajCTF 2025
Last weekend, I participated in BlahajCTF 2025 with a few friends from secondary school. Among the many pwn challenges given, I solved all but two. “fastnotes”, by FS, is one of th
-
UMDCTF 2025 - one-write
Writeup for the pwn challenge one-write in UMDCTF 2025
Back in April, I participated in UMDCTF 2025 with the Singapore Student Merger (SSM). There were a few challenges that I did not manage to solve at the time, and pwn/one-write was
-
Sieberrsec CTF 2025
Writeups for qualifiers and finals of Sieberrsec CTF 2025
This previous weekend, I had the privilege of attending both the qualifiers and finals of Sieberrsec CTF 2025, a CTF competition held by the Hwa Chong Institution (HCI) of Singapor