Sacred Key
Category: Forensics
Author: Tejaswi Hegde
Answer / Flag: MAZE{Pow3r_1s_p0wer}
Problem Statement
You happen to come accross this strange looking image. It seems as if there is something hidden in it. Maybe you need a key to unlock the answer.
Relevant files / links
Google Drive - https://drive.google.com/file/d/1xPfTCuD7GqNYI2j9tFD-2ULDb6SU-iVx/view?usp=sharing
Hint
Hint 1: Maybe the file does not contain just image data. A thorough analysis might reveal answers.
Hint 2: Text can also be encoded into images in a very clever way.
Solution
Opening the image in a text editor (like Notepad) and scrolling to the end reveals the message “There are 2 prime numbers assosciated with this image. Multiply them and add a .ddns.net at the end. Also remember Romeo Charlie II.”.
The primes numbers are the dimensions of the image: 571 x 431 = 246101
Going to 246101.ddns.net gives us a encoded text: ea3c49872517df291aa780125e42ec61361ab37db9ad0a8d
Coming back to the image, running it through an image analyzer (Like Aperi Solve) / steganography software (steghide) gives us the message “the key is winteriscoming”.
Decoding the text in the jpg file, Romeo = R, Charlie = C, II = 2, which gives us RC2 encryption.
Using the key “winteriscoming”, we can decode the text (RC2 decrypt on a website like Cyberchef) to get the flag.