level5.sh

#!/bin/bash

# Set the flag content
flag="FLAG=QS{Qu1ckSn4tch_Ch4mp10n_2024} Massage=like a true"

# Create the main challenge directory
mkdir -p level5_ctf
cd level5_ctf
  cat << EOF > README.txt
  # Level 5 Instructions: Decoding the Flag

  Welcome to the final level of the challenge!

  ## Objective

  Your objective in this level is to find the flag, which has been encoded using a common encoding method. Once you find the encoded flag, you will need to decode it to reveal the final secret.

  ## Decoding with \`base64\`

  The encoding used in this level is **base64**. To decode a base64 encoded string, you can use the \`base64\` command with the \`-d\` option.

  ### Usage:

  To decode a base64 string inside a file, use:  \`cat encoded_flag | base64 -d\`

  ## How to Proceed

  1.  **Explore:** Navigate through the directories in this level to find the location of the encoded flag.
  2.  **Locate:** Once found, note the location of the file.
  3.  **Decode:** Use the command above to decode the file contents and reveal the final flag.

  Good luck, and congratulations on making it to the final level!

EOF

# Create a hidden directory
mkdir .secret_stuff
cd .secret_stuff

# Create decoy files
touch decoy1.txt
echo "This isn't the file you are looking for" > decoy1.txt
touch decoy2.txt
echo "Keep searching" > decoy2.txt


# Create the directory and flag file
mkdir data
cd data
echo "$(echo "$flag" | base64)" > encoded_flag
chmod 444 encoded_flag

# Create decoy files in the directory
touch decoy3.txt
echo "This might be important" > decoy3.txt
touch decoy4.txt
echo "Or maybe not?" > decoy4.txt

cd ..
cd ..
# Create a dummy file
dd if=/dev/urandom of=level5_ctf/dummy.bin bs=1M count=2

# Provide some initial setup info to the user
echo "Level 5 Challenge Started!"
echo "You need to explore thoroughly to find the encoded flag. Once you find it you will need to decode it using a specific command."