Jax Dunfee

DaVinci CTF 2023 - Writeups
A few write-ups from this weekends DaVinci CTF.
March 12, 2023

dvCTF was a breath of fresh air, and while I couldn’t fully invest my time it this weekend it was a fun and interesting CTF, one in which I hope inspires others like it. Here are my Write-ups for dvCTF 2023.

Weird Keylogger

David is a notorious French typography enthusiast, but last week he noticed a keylogger under his desk!

He managed to extract a USB capture file but he can’t decode it, perhaps because of his typography shenanigans, can you help him?

Given a file capture.pcapng, we must decrypt the USB traffic.

Doing so we get this: }foo ir;fg j.f /oa, dk iuHJ?Xqwerdkj.fqfkjbfxqralioaxrsjC

Which we can pass into https://www.dcode.fr/keyboard-change-cipher under the decode qwerty ↦ bepo the flag is: dvCTF{bépoisthebestkeyboardlayout}

Lost World

A friend of mine lost his Minecraft world, he even left his dog there, he tried to find the deleted files but the only thing left were the screenshots he took at the beginning of his adventure. Can you at least find the world’s seed so he can start over in the same world?

This one was an interesting one. We are provided 30 screenshots and told to find the world seed.

Screen shots here: https://imgur.com/a/LJsc48V

This immediately made me think of this blog post on finding the original title screen minecraft seed.

Skimming through these, we can instantly discard those without F3 open as they will no help to us.

Some of the resulting information gained is this:

Minecraft version: 1.16.5

614 248  - Desert 
638 315 - Taiga 
29 33 - Desert 
200 73 - Savanna 
464 68 - Plains 
773 -71 - Warm Ocean

*Dungeon Info*
Screenshot is looking at the coordinates 200 39 129, while the spawner itself is at 201 40 129. 

The dungeon resides in a Desert.

And the floor laylout of said dungeon is 


Using this information, we can toss it into SeedCandy which gives us a structure seed of 7372456362496, which we can then toss the biomes into to finally find the seed required for the flag 4696135883896947200

Flag: dvCTF{4696135883896947200}