CTF Challenge: Natas 00

Challenge Overview:

• This was the following description for the challenge. Also note that level 0 and level 1 are combined for this challenge.

What is SSH?

SSH (Secure Shell) is a cryptographic network protocol used to securely connect to remote servers. It provides:

• Encrypted communication: All data sent between your computer and the remote server is encrypted
• Remote command execution: You can run commands on a remote machine as if you were sitting at its keyboard
• Authentication: Uses username/password or cryptographic key pairs to verify identity
• Security: Replaces insecure protocols like Telnet with authenticated, encrypted connections

SSH is one of the most fundamental tools in cybersecurity and system administration. For CTF challenges, SSH is often the entry point to access challenge servers.

The Challenge

Your goal is to log into the OverTheWire Bandit challenge server using SSH with the following credentials:

• Host: bandit.labs.overthewire.org
• Port: 2220
• Username: bandit0
• Password: bandit0

SSH Command Breakdown

The command to connect via SSH is:

ssh -p 2220 bandit0@bandit.labs.overthewire.org

Let’s break this down:

• ssh: The SSH command itself
• -p 2220: The -p flag specifies a custom port. By default, SSH runs on port 22, but this server uses port 2220
• bandit0: The username to log in with
• @bandit.labs.overthewire.org: The @ symbol separates username from hostname (the server address)

Enter the password

When prompted, type the password:

bandit0@bandit.labs.overthewire.org's password: 

Type bandit0 (it won’t show as you type for security)

After logging in, you’ll be at the command prompt.

Now that we’re connected, we need to find the password for the next level. Here’s how:

List the directory contents with ls

First, use the ls command to see what files are in the current directory:

• ls: Lists all files and directories in the current location
• The output shows there’s a file called readme - this is likely where the password is hidden

Read the file with cat

Use the cat command to display the contents of the readme file:

• cat: Short for “concatenate”, this command reads and displays the contents of files
• readme: The filename to read

Save the password

Important: Make sure to save this password somewhere on your machine because you’ll need it for the next challenge (Bandit Level 1).

Save to a text file using cat redirection

PathogenicKatt@PathogenicKatt:~$ cat > next_passwd.txt
[Paste the password here]

Then press Ctrl + D to save and exit. This creates a file with the password.

• cat >: Redirects output to create/overwrite a file
• next_passwd.txt: The filename where the password will be saved
• Press Ctrl + D: Tells the system you’re done typing

Next step: We are going to use the password we found to log in for Bandit Level 1!