Bandit Level 2 to 3: The Ultimate Filename Challenge

Introduction

Welcome to the next stage of the Bandit wargame. This level, from 2 to 3, introduces a filename that brilliantly combines the challenges of the previous two levels. We’ll need to handle a name that not only contains spaces but also starts with double hyphens (--), which can be confused for command options.

Mastering this challenge will solidify your understanding of how the Linux shell parses filenames and arguments.

The Challenge: Level 2 Goal (Updated)

The password for the next level is stored in a file with a particularly tricky name located in the home directory:

--spaces in this filename--

This filename is designed to break simple commands. Let’s see how to tackle it.

Step-by-Step Walkthrough

Here is the breakdown of how to solve this puzzle.

Step 1: Log into bandit2

As always, start by using the password from the previous level to SSH into bandit2.

ssh [email protected] -p 2220

Step 2: Discover the File

List the files in the home directory to see our target.

bandit2@bandit:~$ ls
--spaces in this filename--

The file is there, just as described.

Step 3: The Problem - Why Simple Methods Fail

Let’s see what happens when we try the methods from the previous levels in isolation.

1. Just using cat: The shell will interpret --spaces as an option for cat, and the rest as separate arguments. This will fail.

   bandit2@bandit:~$ cat --spaces in this filename--
   cat: unrecognized option '--spaces'
   Try 'cat --help' for more information.

2. Just using quotes: Quoting correctly groups the name into a single argument, but that argument still starts with --. The cat command will still think it’s an option, not a filename.

   bandit2@bandit:~$ cat "--spaces in this filename--"
   cat: unrecognized option '--spaces in this filename--'
   Try 'cat --help' for more information.

We need a more robust solution that handles both issues at once.

Step 4: The Combined Solution

The key is to tell the shell explicitly that this is a file path, not an option.

Method 1: Specifying the Path (Recommended)

This is the most reliable method. By prepending ./ to the filename, you tell the shell to look for a file in the current directory (.). This prevents the cat command from ever interpreting the name as an option. We still need quotes to handle the spaces.

bandit2@bandit:~$ cat "./--spaces in this filename--"

This command works perfectly and will display the password for bandit3.

# yours might be different
MNk8KNH3Usiio41PRUEoDFPqfxLPlSmx

Method 2: Using the -- Separator

Another powerful technique is to use a double-dash (--) as a separate argument for the cat command. This special argument tells cat (and most other standard Linux commands) to stop processing options. Every argument that comes after the -- will be treated as a literal filename.

bandit2@bandit:~$ cat -- "--spaces in this filename--"

This also works flawlessly. The first -- is for cat, and the quoted string is the filename we want to open.

Key Concepts Learned

1. Combining Techniques: Real-world scenarios often require you to combine multiple command-line tricks. In this case, we used both path specification (./) and quoting ("...") to solve the problem.
2. The -- Separator: The utility of the -- argument is reinforced here. It’s a lifesaver for programmatic scripts or any situation where filenames might start with a hyphen.
3. Order of Operations: The shell first processes quotes and paths, then passes the resulting arguments to the command. The command then parses those arguments as options or filenames. Understanding this order is key.

Conclusion

Excellent work! By solving this level, you’ve demonstrated a strong grasp of how to handle even the most inconveniently named files. You’ve now earned the password for bandit3.

Keep this momentum going as you log out and move on to the next challenge!