COMPFEST CTF 2023 - Not A CIA Test
Description
Category: OSINT
That night was definitely the happiest of my life. I get to spend a night with my favorite girl, walking and strolling around the streets of Seoul, holding hands and enjoying the winter air with the beautiful night lights decorating our surroundings. Look, I even took a picture of her! Although, she was really camera-shy. What I don’t really get is, my friends told me that all of this is just in my imaginations. I can assure you I did have a date with her. Otherwise, how would I take this picture?!
Anyway, I organize my dating pictures by location. The problem is, I forgot the name of the street where I took this picture, specifically the street behind her. And the girl? Well, long story, but there’s no way I can ask her. All I can remember is this location was near a Burberry store. I tried to look it up too, but the streets and buildings were pretty hard to recognize because the pictures on the internet were from 5 years ago.
I know you can find the street location. So please help me, yeah? Also, sorry for the pixellated image!
NOTE: Brute-force solutions in the writeups will not be considered valid.
Flag format: COMPFEST15{StreetNameWithoutDash_DistrictName_BurberryStorePlusCode}
Example: COMPFEST15{BanpoDaero_Geumjeong_RRXH+88}
Author: notnot
Attachments:
Resolution
1. Initial hints
I searched Burberry near Seoul, South Korea on Google Maps according to the hints in the description:
There are a lot of Burberry shop, we need more information to reduce the number.
On the picture we can see a sign which indicate a location but it’s too blurry to see any text:
2. Identify the sign
We need to find the same image with a better resolution. For this, I used Google reverse image seach to find similar pictures with better resolution:
I found one with a good resolution on Twitter:
Now we can read some text from the sign: J????? H???g??g Park
We search for J H Park in Seoul on Google Maps and we found one with a very similar name with the text on the sign:
3. Find the Burberry shop
Now we know that the Burberry shop we are looking for is near the Jamwon Hangang Park, we can find it on Google Maps with this input Burberry near Jamwon Hangang Park.
Now there is only one Burberry shop possible:
We use the Street view to verify that it’s the same location as in the picture.
Despite some changes in the area, there are still the same buildings:
 |
 |
The street is 459 Dosan-daero, Gangnam-gu, Seoul, South Korea and the Plus Code is G2FW+QP Seoul, South Korea.
Finally we got the flag with the right format: COMPFEST15{DosanDaero_Gangnam_G2FW+QP}.