After decoding Base64, we now face our first real cipher in Bandit Level 11 to 12. The password isn’t encoded for data transport; it’s been deliberately obfuscated using a simple character-shifting algorithm.

This level introduces the Caesar cipher, one of the oldest and most well-known forms of encryption. We’ll learn how to crack it with tr, a command-line utility for translating characters. 📜

The Challenge: Level 11 Goal

The level’s objective is described as follows:

So far, we’ve located files, filtered their contents, and even extracted text from binary data. Bandit Level 10 to 11 introduces a new core concept: data encoding. The password is in plain sight, but it’s been transformed into a different format.

This level teaches us how to recognize and reverse Base64 encoding, a common method for representing binary data as text. 🧑‍💻

The Challenge: Level 10 Goal

The objective for this level is straightforward:

In our journey so far, we’ve dealt mostly with plain text files. Bandit Level 9 to 10 introduces a new type of challenge: extracting information from a binary file. These files are compiled for machines, not humans, and reading them with cat results in a mess of unreadable characters.

This level teaches us how to use the strings command, a specialized tool for finding and printing the sequences of readable text embedded within binary data. 🧐

In the last level, we used grep to find a known pattern in a file. For Bandit Level 8 to 9, the challenge is more abstract: we need to find a line that is unique within a file filled with duplicates. The password isn’t next to a keyword; the password is the unique line itself.

This requires us to move beyond single commands and learn how to create a pipeline, chaining multiple tools together to perform a complex data analysis task in a single line.

We have successfully used the find command to locate files based on their metadata. Now, for Bandit Level 7 to 8, our focus shifts from finding the file to finding specific data inside a file.

This level introduces grep, one of the most fundamental and widely used text-processing utilities in the Linux command-line world. 🕵️

The Challenge: Level 7 Goal

The goal for this level is described as follows:

In the previous level, we used find to search within a specific directory. Now, in Bandit Level 6 to 7, we’re taking the training wheels off. The password file could be anywhere on the entire server, and we must once again use its properties to locate it.

This level introduces the challenge of running a search with broad scope, which often generates a lot of noise. We will learn how to filter out that noise to find exactly what we’re looking for.

So far in the Bandit wargame, we’ve found files based on their names or by looking in specific places. Level 5 to 6 takes a significant step up in complexity and introduces one of the most powerful file-searching utilities in Linux: the find command.

Instead of a name, we are given a set of properties—metadata—that describe the file containing the password. Our task is to translate these properties into a command that can sift through a maze of directories to find our target.

In the last level, we learned to find files that were intentionally hidden from view. Now, in Bandit Level 4 to 5, the challenge is different. The password file isn’t hidden, but it’s lost in a crowd of other files that are unreadable to humans.

This level teaches us a critical skill: how to programmatically identify the type of data a file contains, allowing us to quickly find the needle in the haystack.

After navigating tricky filenames, Bandit Level 3 to 4 introduces us to a core concept of Linux/Unix-like operating systems: hidden files. These files, often used for configuration, don’t show up in normal directory listings simply because their names begin with a dot.

This level will teach you how to look past the obvious and uncover the secrets hidden within a directory.

The Challenge: Level 3 Goal

The official goal on the OverTheWire website states:

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.