Using Hydra to Crack Passwords

Introduction

Welcome to "Cybersecurity with Hands-On Labs". This course is designed for beginners with basic Linux knowledge who are interested in understanding the fundamentals of cybersecurity. In this hands-on session, you'll learn about password vulnerabilities and how to use a popular security tool called Hydra.

In this lab, you'll explore the concept of password security by simulating a brute-force attack on a practice website. You'll learn how to use Hydra, a powerful tool used by security professionals to test password strength. This experience will help you understand why strong passwords are crucial and how easily weak passwords can be compromised.

By the end of this lab, you'll have practical experience with:

1. Setting up and exploring a practice website
2. Understanding common password lists and their security implications
3. Using Hydra to simulate a brute-force attack
4. Analyzing results and appreciating the importance of strong passwords

Let's begin our journey into the world of password security!

Skills Graph

Exploring the Target Website

In this step, we'll examine the website we'll be testing and introduce the concept of brute-force attacks.

Open the Web 8080 tab in your lab environment. You should see a simple login page with fields for a username and password.

Try logging in with these credentials:

• Username: test, Password: password123
• Username: admin, Password: admin

You'll receive an "Invalid username or password" message each time. This is a common security practice that doesn't reveal whether the username or password is incorrect, preventing potential attackers from gathering information about valid usernames.

Notice that there's no limit on login attempts. In real-world secure systems, you might get locked out after several failed attempts to prevent brute-force attacks.

What you've just done manually - trying different username and password combinations - is the basic idea behind a brute-force attack. Attackers automate this process to try thousands or even millions of combinations quickly. This demonstrates why using strong, unique passwords is crucial for security.

Examining the Password List

Now that we understand the basic concept of a brute-force attack, let's examine a list of common passwords that attackers might use.

Switch back to the Desktop Tab in your lab environment.

Open the Xfce Terminal on the Desktop.

In real-world scenarios, attackers often use extensive lists of passwords from past data breaches. For our lab, we'll use a smaller list of common weak passwords found on the internet. This list has already been prepared for you and is located at /home/labex/project/500-worst-passwords.txt.

Let's examine the contents of the file:

head -n 10 500-worst-passwords.txt

You should see the first 10 passwords from the list.

These passwords are common choices that many people unfortunately still use. This is precisely why attackers often try these first in their attempts to gain unauthorized access. By using a list like this, an attacker can greatly speed up their brute-force attack. Instead of trying every possible combination of characters (which could take years), they start with the most likely passwords, significantly increasing their chances of quick success.

Note: This data comes from the internet. If you're interested, you can view the source of this list at: https://gist.github.com/5fd1a736a0df2892b5f0ab61ac4bd045.git

Setting Up Hydra

Now that we have our list of passwords, let's set up Hydra, the tool we'll use to automate our brute-force attack simulation.

First, let's create a file with usernames to try:

cd ~/project
echo -e "admin\nuser\nroot" > ~/project/usernames.txt
cat ~/project/usernames.txt

This creates a file with three common usernames: admin, user, and root. We'll use this file in our Hydra command later.

Now, let's install Hydra. Run these commands:

sudo apt-get update
sudo apt-get install hydra -y

Hydra is a popular tool used by security professionals and ethical hackers to test password security. It can perform rapid dictionary attacks against various network services. It works by taking a list of usernames and a list of passwords, then systematically trying each combination on the target system.

Once the installation is complete, you can check that Hydra is installed correctly by running:

hydra -h

This will display the help information for Hydra, showing all its options and capabilities.

Using Hydra for Password Cracking

Now that we have Hydra installed and our password list ready, let's use it to simulate a brute-force attack on our practice website.

Run the following Hydra command:

hydra -L ~/project/usernames.txt -P ~/project/500-worst-passwords.txt localhost -s 8080 http-post-form "/:username=^USER^&password=^PASS^:Invalid username or password" -o ~/project/hydra_results.txt

Let's break down this command:

• hydra: The name of the tool we're using.
• -L ~/project/usernames.txt: Use this list of usernames.
• -P ~/project/500-worst-passwords.txt: Use this list of passwords.
• localhost -s 8080: The address of the website we're testing.
• "/:username=^USER^&password=^PASS^:Invalid username or password": Tells Hydra how to interact with the login form.
• -o ~/project/hydra_results.txt: Save the results to this file.

Hydra will start running, and you'll see output as it tries each username and password combination. This process might take a few minutes.

After Hydra finishes, examine the results:

cat ~/project/hydra_results.txt

You should see lines indicating successful login attempts, like "login: [username] password: [password] found".

Consider the implications of what you've just done:

• Hydra tried hundreds of password combinations in just a few minutes.
• It successfully found working credentials.
• This demonstrates why using common or weak passwords is dangerous. A real attacker could try thousands or even millions of passwords very quickly.

Reflect on how this automated process differs from the manual attempts you made in Step 1. The speed and efficiency of tools like Hydra make weak passwords a significant security risk.

Summary

In this lab, you've gained practical experience with password security and ethical hacking techniques. You've learned:

1. The concept of brute-force attacks and why they're effective against weak passwords.
2. How to use Hydra, a real-world security tool, for password cracking.
3. The importance of strong, unique passwords in defending against these attacks.

Remember, the goal of this lab was to understand password security, not to hack real accounts. Always use your knowledge ethically and legally.

This experience underscores why cybersecurity experts strongly advise against using common or easily guessable passwords. As you continue your journey in cybersecurity, you'll encounter many more tools and techniques. Keep learning, stay curious, and always use your skills responsibly!