Apples 🍎

OSINT 300 pts Hard

Challenge Information

  • Challenge Name: Apples
  • Category: OSINT
  • Points: 300 pts
  • Description: "An apple a day keeps a shinigami awake."
  • File: light_and_ryuk.py
  • Hint: References Death Note (apples and shinigamis)
  • Flag: EOF{apples_apples_everywhere_raaaah}

Solution Methodology

Step 1: Running the Python Script

We started by running the given Python file:

python3 light_and_ryuk.py

This printed a YouTube video link in the terminal.

Step 2: Inspecting the YouTube Video

Opening the YouTube link revealed something interesting in the comments section — there was a Google Drive link, but it appeared to be encrypted using a Caesar cipher.

Step 3: Decrypting the Caesar Cipher

Instead of writing a script, we used an online Caesar cipher decryption tool. Trying different shifts revealed the decrypted Google Drive link that pointed to an image file named kira.png.

Caesar Cipher Decryption

The encrypted Drive link was shifted using a Caesar cipher. Testing different rotation values (ROT1-25) revealed the correct plaintext URL.

Step 4: Downloading and Analyzing the Image

We downloaded the file from Google Drive. The image looked normal, but we suspected hidden data, so we used the strings command to search for the flag pattern:

strings kira.png | grep EOF

Step 5: Discovery

The output revealed:

EOF{apples_apples_everywhere_raaaah}

This was the hidden flag, embedded at the end of the PNG file.

Flag: EOF{apples_apples_everywhere_raaaah}

The flag references Ryuk's love of apples from Death Note! 🍎

Key Insights

Multi-Stage OSINT Challenge

  1. Execute Python script to get YouTube link
  2. Find encrypted Google Drive link in YouTube comments
  3. Decrypt Caesar cipher to reveal Drive URL
  4. Download image from Google Drive
  5. Extract hidden text using strings command

Death Note Theme

  • "apple a day keeps a shinigami awake" - Ryuk loves apples
  • light_and_ryuk.py - Light Yagami and Ryuk are characters
  • kira.png - Kira is Light's alias
  • Flag message - References Ryuk's apple obsession

Tools Used

Tool / Command Purpose
python3 light_and_ryuk.py Get YouTube link
Browser Check YouTube comments
Online Caesar tool Decrypt Drive link
Google Drive Download kira.png
strings kira.png | grep EOF Found flag

Summary Table

Step Action Result
1 Run the Python script Got YouTube link
2 Checked YouTube comments Found Caesar-encrypted Drive link
3 Decrypted Drive link Got real Drive URL
4 Downloaded image Got kira.png
5 Extracted hidden text Found flag

Challenge Theme: Death Note

This challenge cleverly incorporates Death Note references:

  • Ryuk - The shinigami who loves apples 🍎
  • Light Yagami (Kira) - The main protagonist
  • Apples keeping shinigami awake - Ryuk's addiction
  • Multi-layer puzzle - Like the cat-and-mouse game in the show

A creative OSINT challenge that combines pop culture with technical skills! 📓