SDCTF2025 Writeup
Challenge Directory
Challenge Name: Piotr's Day Off: Day 2
To get context for this challenge, you would have to read the description of the previous day, and here it is:
So… We know that Piotr was last seen at the Sun God Festival in San Diego. The sun god festival happened on Saturday, May 3rd, and I already knew this as I was physically there, but I assume that you can probably find this information online.
I didn’t know that I was solving for Day 2 initially, but since this is a writeup for that day, here’s the description for Day 2:
Ahh yes, the infamous no more info challenge description. Anyway, at first I didn’t really know where to start, and the only lead that I did have was that Piotr was last seen at the Sun God Festival, and that he is a board member of ACM @ UCSD. I decided to really look into that first bit of information.
I went onto google and searched for wooli piotr, and I found something quite interesting:
The first instagram link led to this, which was a post made by Piotr:
This was posted on May 5th, 2025, which was when I realized that this might be the flag to challenge corresponding to Day 2.
I then decided to reverse image search this photo, and I found that it was actually a photo of Piotr at the Kitty Hawk Pier in North Carolina:
So I tried submitting that and thus here’s the flag for Day 2:
Flag: Kitty Hawk
Challenge Name: Piotr's Day Off: Day 4
Here’s the description for Day 4:
I decided to go to the ACM @ UCSD website to see if there was any information about Piotr, and I found this:
Then I searched up his name on google, and these were the results:
Went onto LinkedIn and found this:
I then clicked on the link he had there, which led to this:
I tried reverse image searching this, but it always led be back to somewhere in San Diego, Sunset Cliffs.
I then tried clicking on the link at the bottom to go to his GitHub:
Here’s his GitHub:
I then explored the repository he had on there, looking through the commits to see if there was anything interesting, and I found this:
Check out my Xeets on X.
hmm… how suspicious. I then went looking through his deployments, and I found a very interesting red “X”:
wow we just got his username for X just like that!
Here were some of his tweets, but that link at the top seems to be quite interesting:
Clicking on that leads to this, and that gas station is definitely not in Texas:
I had to search for a little bit, but I eventually found a reference to Tunisia and their gas station stock pics:
Finally, I serarched up a list of Tunisian cities, and the flag ended up being the first result:
Flag: Tunis
Challenge Name: Piotr's Day Off: Day 5
Here’s the description for Day 5:
This challenge continued on from the previous day, and here’s the clue, another truth social post by Piotr:
I went onto bluesky and searched up Piotr’s Truth Social username, and thanks to the auto suggestions, I was able to find his account:
I found a series of Bluesky posts, or whatever you call them, and here they are:
From here, I was able to deduce that “magic die zusammenkunft” is Magic the Gathering in German, from which I now know Piotr may be in Germany.
I then scoured google for Magic the Gathering events in Germany, and I didn’t really find anything. I also searched for Smash Brothers events in Germany, but no dice here either.
I then decided to search for smash brothers events in general, and what is that first link that I see?? A REDDIT POST????:
Next, I decided to CTRL + F the page for “Germany” and I found this to be quite interesting:
I tried submitting that as the city, and there it was! It perfectly matched the dates that Piotr was there, and thus the flag was found:
Flag: Großlohra
It was interesting that this flag had a special character in it, and I was not expecting that at all. I thought it was going to be a simple city name, but I guess not! 😅
I wasn’t really able to find the other flags in time, but honestly I was just using my phone to search for all of this, I assume it would have been a lot easier if I had used my computer instead hahaha. It was still quite a fun series of challenges, and I really enjoyed the process of solving them. I hope you enjoyed reading this writeup as much as I enjoyed writing it! 😁