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My CTF Journey in 2025

Hello all!

As the title of this post says, I want to do an overview of the CTFs i partecipated in during 2025.

Why? just because. I want to keep track of the progress, and maybe this will keep me motivated enough to partecipate in more of them? maybe!

The creation date of this post is: 18/07/2025. Last update: 24/08/2025.

August

BrunnerCTF 2025

Challenges Completed:

  • Rev
    • Grandma’s Predictable Cookies (100)

I just wanted to solve a single challenge and it went good, I guess.

This challenge was the classic “RNG using time as seed and you know the seed” type of thing. I wrote the solution in C in something like 10 minutes, but I spent a fucking hour debugging because it didn’t gave me the flag. The code was right!

At one point, I was about to give up. Then I remembered that I’m fucking dumb, the binary to reverse was a linux x64 ELF, while I was building and running the resolution code on my ARM MacOS. TIL that the implementation of rand() is platform-specific.

I ran the initial version of the code on a x64 linux and it immediately found the flag. This is literally my stupidity punishing me for buying a Mac.

July

DownUnderCTF 2025

Challenges Completed:

  • Rev
    • Zeus (100)
  • Web
    • Philtered (100)
    • secure email attachments (100)
    • mini-me (100)
  • Misc
    • discord (100)
    • our-lonely-dog (100)

Went meh, but I really had no time this weekend so I guess it’s okay.

I started to work against “gomail”, but I haven’t managed to finish it. I quickly read the writeup at the end of the event and I remember that was was something about an overflow in the session structure during the serialization, something like that. I’d like to retry the challenge it with this “partial” hint, but I’m going on vacation soon so I don’t know if I’ll have enough time.

L3akCTF 2025

Challenges Completed:

  • Misc
    • Sanity Check (50)
    • Puzzles - 1 (50)
  • OSINT
    • Sunny Day (50)
    • Mountain View (50)
    • Lost Locomotives (50)
    • Grain of Truth (50)
    • Elephant Enclosure (50)
  • Hash Cracking
    • Mildly Disastrous Security (50)
  • Rev
  • Web

Good challs but really disappointed by how little i managed to do, not trying to find any excuses. It’s been quite a big while since the last time i did a CTF, so i need to get a bit more used to the loop and keep pushing.