TryHackme’s Advent of Cyber 2023 — Day 3 Writeup

Brute Forcing [ Hydra Is Coming To Town ] — The server room is locked down. The team needs to regain access to recover backup tapes. Brute-forcing the PIN panel might be the only option!

Learning Objectives

After completing this task, you will understand:

Password complexity and the number of possible combinations

How the number of possible combinations affects the feasibility of brute force attacks

Generating password combinations using crunch

Trying out passwords automatically using hydra

Counting the Passwords

Let’s consider an imaginary scenario where the password is exactly four characters, and each character can be:

• A digit: We have 10 digits (0 to 9)
• An uppercase English letter: We have 26 letters (A to Z)
• A lowercase English letter: We have 26 letters (a to z)

Therefore, each character can be one of 62 different choices. Consequently, if the password is four characters, we can make 62×62×62×62 = 624 = 14,776,336 different passwords.