OverTheWire

Introduction

Ready to dive into the OverTheWire Bandit CTF series? 🕵️‍♂️ This walkthrough is a guide. Whether you’re a beginner or looking to brush up your basics, the Bandit series is perfect for honing your Linux command-line skills while navigating realistic scenarios.

Before You Start: Make sure to check out the rules to ensure a fair and fun experience.

This guide covers:

  • Detailed objectives for each level.
  • Commands and step-by-step solutions.
  • Explanations to help you understand the “why” behind each step.

Let’s gear up, fire up your terminal, and tackle these challenges head-on!

note: for each level at ssh increase the count before the username bandit0 , bandit1, bandit3, bandit4... and so on.

Level 0

  • Objective : Connect to the Bandit server via SSH.
  • Steps:
    1. SSH into the server with the provided credentials.
    2. The username is bandit0, and the host is bandit.labs.overthewire.org.
    3. Use port 2220 instead of the default port 22.
    4. password is bandit0
  • Command: 
    ssh bandit0@bandit.labs.overthewire.org -p 2220

    and level0 -> level1 begins

Level 0 -> Level 1

  • Objective: The password for the next level is stored in a file called readme located in the home directory.
  • Command: 
    ssh bandit0@bandit.labs.overthewire.org -p 2220
    1. locate the file by find readme or ls command.
    2. use cat readme to read the content in the file.
  • Password: ZjLjTmM6FvvyRnrb2rfNWOZOTa6ip5If
  • Explanation: SSH (Secure Shell) is a protocol to connect to remote servers securely. Here, we use the username and host details along with a non-standard port.

Level 1 -> Level 2

  • Objective: Read a file named - in the home directory.
  • Steps:
    1. Use ls to list the files in the directory. 
      ls
    2. Notice a file named -. This is tricky because - is often treated as an option by commands.
    3. To read the file, prefix the name with ./ to indicate it’s a file.
  • Command: 
    cat ./-
  • Password: 263JGJPfgU6LtdEvgfWU1XP5yac29mFx
  • Explanation: The ./ tells the shell that - is a file in the current directory and not an option for the cat command.

Level 2 -> Level 3

  • Objective: Read a file with spaces in its name.
  • Steps:
    1. Use ls to list the files in the directory. 
      ls
    2. You’ll see a file named spaces in this filename.
    3. To read it, enclose the name in quotes or escape the spaces with \.
  • Command: 
    cat "spaces in this filename"
  • Password: MNk8KNH3Usiio41PRUEoDFPqfxLPlSmx
  • Explanation: Quotes or escape characters allow you to handle file names with special characters or spaces.

Level 3 -> Level 4

  • Objective: Find and read a hidden file.
  • Steps:
    1. Use ls to list files, but it won’t show hidden ones (files starting with .).
    2. Use ls -a to include hidden files in the listing. 
      ls -a
    3. You’ll see a hidden directory named inhere. Navigate into it and list files again.
    4. Inside, find a hidden file named .hidden and read it.
  • Command: 
    cat inhere/.hidden
  • Password: 2WmrDFRmJIq3IPxneAaMGhap0pFhF3NJ
  • Explanation: The -a flag with ls lists all files, including hidden ones. Hidden files are often used to store sensitive data.

Level 4 -> Level 5

  • Objective: Find the password in one of multiple files.
  • Steps:
    1. Use ls to see multiple files named file01, file02, etc., in the inhere directory.
    2. Read all the files manually or use a single command to output them together.
  • Command: 
    cat inhere/file*
  • Password: 4oQYVPkxZOOEOO5pTW81FB8j8lxXGUQw
  • Explanation: The * wildcard matches all files starting with file. This saves time compared to reading files one by one.

Level 5 -> Level 6

  • Objective: Search for a file of a specific size (1033 bytes).
  • Steps:
    1. Use the find command to search for files meeting specific criteria. 
      find . -type f -size 1033c
    2. -type f ensures you’re only looking for files.
    3. -size 1033c looks for files exactly 1033 bytes (c stands for bytes).
  • Password: HWasnPhtq9AVKe0dmk45nxy20cvUa6EG
  • Explanation: The find command is powerful for locating files based on attributes like size, ownership, and permissions.

Level 6 -> Level 7

  • Objective: Find a file owned by a specific user and group.
  • Steps:
    1. Use find with additional filters for ownership and size. 
      find / -type f -user bandit7 -group bandit6 -size 33c 2>/dev/null
    2. -user and -group filter by the file’s owner and group.
    3. 2>/dev/null suppresses permission errors during the search.
  • Password: morbNTDkSW6jIlUc0ymOdMaLnOlFVAaj
  • Explanation: Combining filters helps narrow down the results to the exact file you’re looking for.

Level 7 -> Level 8

  • Objective: Search for the password beside the keyword “millionth”.
  • Steps:
    1. Use grep to search for the keyword directly in the file. 
      grep millionth data.txt
    2. The password will be displayed next to the keyword.
  • Password: dfwvzFQi4mU0wfNbFOe9RoWskMLg7eEc
  • Explanation: grep is a tool for searching text patterns in files.

Level 8 -> Level 9

  • Objective: Find the only unique line in a file.
  • Steps:
    1. Use sort to arrange lines, then uniq -u to filter out duplicate lines. 
      sort data.txt | uniq -u
    2. This command outputs the line that appears only once.
  • Password: 4CKMh1JI91bUIZZPXDqGanal4xvAg0JM
  • Explanation: Sorting is necessary because uniq only works on consecutive identical lines.

Level 9 -> Level 10

  • Objective: Extract the password from printable strings starting with ==.
  • Steps:
    1. Use strings to extract readable text from the file. 
      strings data.txt | grep ==
    2. Filter the results using grep.
  • Password: FGUW5ilLVJrxX9kMYMmlN4MgbpfMiqey
  • Explanation: strings is handy for reading text from binary files.

Level 10 -> Level 11

  • Objective: Decode a Base64-encoded string.
  • Steps:
    1. Use base64 with the -d flag to decode the file content. 
      base64 -d data.txt
    2. The decoded string contains the password.
  • Password: dtR173fZKb0RRsDFSGsg2RWnpNVj3qRr
  • Explanation: Base64 encoding is often used to represent binary data in ASCII format.

Level 11 -> Level 12

  • Objective: Decrypt a ROT13-encoded file.
  • Steps:
    1. Use the tr command to perform the ROT13 transformation. 
      cat data.txt | tr 'a-zA-Z' 'n-za-mN-ZA-M'
    2. The password will be revealed after decryption.
  • Password: 7x16WNeHIi5YkIhWsfFIqoognUTyj9Q4
  • Explanation: ROT13 shifts each letter by 13 places, a simple substitution cipher.

Up Next

To be cont… XD