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I remember the first time I attempted a brute force attack. Sitting in a bustling Manila café, armed with just my Android phone and Termux, I felt both excitement and apprehension.

Using Hydra, I targeted a local test server, eager to understand the mechanics behind web login vulnerabilities. That experience ignited my passion for ethical hacking and the importance of securing web applications.​

In this guide, we’ll delve into performing brute force attacks on HTTP/HTTPS forms using Hydra in Termux. Whether you’re a budding ethical hacker or a developer aiming to bolster your application’s security, this tutorial offers practical insights.

Let’s embark on this journey to fortify our digital defenses.

⚠️ Important: These tools are intended for ethical hacking, security research, and education. Use them only on systems and networks you own or have permission to test. Unauthorized use can lead to serious legal consequences.

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Table of Contents

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• Real-World Application Scenarios for Practicing Brute Force Attacks
  • 1. Local Test Environments
  • 2. TryHackMe and Hack The Box
  • 3. Bug Bounty Programs
• Prerequisites
• Installing Hydra on Termux
• Breaking Down a Hydra Command (Line by Line)
• Performing a Brute Force Attack on an HTTP Login Form
  • Example Command for an HTTP Login Form:
• Brute Force Attacks on HTTPS Forms
  • Command for HTTPS Login Form
• Creating a Password List for Brute Force Attacks
• Ethical Considerations and Security Best Practices
  • How to Defend Against Brute Force Attacks
    • 1. Rate Limiting & Account Lockouts
    • 2. Use CAPTCHA
    • 3. Multi-Factor Authentication (MFA)
    • 4. Password Hygiene and User Education
    • 5. Monitoring and Logging
• Fortify Your Web Security Arsenal

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Real-World Application Scenarios for Practicing Brute Force Attacks

Before you jump headfirst into launching brute force attacks using Hydra, you need to understand one critical rule: always have permission. Practicing without consent can land you in legal trouble fast. Thankfully, there are safe and ethical environments where you can refine your skills.

1. Local Test Environments

One of the safest ways to learn is by building your own playground:

• Set up a basic web server on your Android device using PHP + MariaDB + Apache inside Termux.
• Create a mock login form (login.php) and connect it to a dummy database of usernames and passwords.
• Then use Hydra to test that form using sample credentials from custom password lists.

This setup lets you understand how brute force attacks work from both the attacker and defender’s perspectives.

2. TryHackMe and Hack The Box

Platforms like TryHackMe and Hack The Box offer guided labs and challenges designed to teach offensive and defensive security in controlled environments. These labs often include brute force login exercises and are perfect for beginners.

3. Bug Bounty Programs

If you’re ready to level up, consider participating in responsible disclosure or bug bounty programs like those hosted on HackerOne or Bugcrowd. These platforms offer real-world applications that you can legally test — and even get paid for finding vulnerabilities.

Reminder: If you didn’t write it, own it, or get permission to test it — don’t touch it. Stick to ethical hacking and you’ll be building skill, not a rap sheet.

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Prerequisites

Before diving into brute force attacks with Hydra, ensure you have the following:

1. Termux Installed: Download Termux from the Google Play Store or its GitHub page.
2. Hydra Installed: Hydra is not included by default, so you need to install it manually. Instructions will be provided below.
3. Target Website with Login Form: Obtain explicit permission to conduct brute-force tests on the target website. Unauthorized hacking is illegal and unethical.

Start by updating Termux to keep all packages current:

pkg update && pkg upgrade

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Installing Hydra on Termux

To conduct brute force attacks on web login forms, you first need to install Hydra in Termux. Follow these steps:

Update Termux Packages: Run the following command to ensure all packages are updated:sqlCopy codepkg update

Install Hydra: Execute this command to install Hydra

pkg install hydra

Verify Hydra Installation: Confirm that Hydra is functioning by executing:

hydra -h

If successful, you should see Hydra’s help menu, indicating that it is ready for use.

With Hydra installed, you can begin your testing for vulnerabilities through brute force attacks.

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Breaking Down a Hydra Command (Line by Line)

A lot of Hydra tutorials throw a command at you and move on. But let’s actually break it down, piece by piece, so you know what you’re typing and why it matters.

Here’s a sample command for attacking a web form:

hydra -L users.txt -P passwords.txt http-post-form "login.php:user=^USER^&pass=^PASS^:F=incorrect"

Now let’s unpack that:

• hydra: This calls the tool itself.
• -L users.txt: This tells Hydra to use the file users.txt for the list of usernames. The -L stands for “login list.”
• -P passwords.txt: This tells Hydra to use the file passwords.txt for the list of potential passwords. The -P stands for “password list.”
• http-post-form: This specifies the attack module, in this case an HTTP POST form.
• "login.php:user=^USER^&pass=^PASS^:F=incorrect": This whole string tells Hydra:
  • The target form is login.php.
  • Replace ^USER^ and ^PASS^ with usernames and passwords from the files.
  • If the response includes the string “incorrect”, the login failed — so keep trying.

Pro tip: You can also change the failure string (F=incorrect) to whatever message the site returns on a failed login, such as "F=Invalid credentials" or "F=Login failed".

Once you understand the anatomy of the command, you can confidently adapt it to different targets and forms. Hydra becomes less of a blunt instrument and more of a precision tool.

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Performing a Brute Force Attack on an HTTP Login Form

Executing brute force attacks on web login forms involves repeatedly attempting various username-password combinations until the correct pair is found. Hydra supports both HTTP POST and GET methods, which slightly alters the command syntax depending on the type of form being targeted.

Here’s the basic command for an HTTP brute-force attack:

hydra -l <username> -P <password_list> <target> http-post-form "/login.php:user=^USER^&pass=^PASS^:F=incorrect"

• -l <username>: Specifies the username for the attack.
• -P <password_list>: Points to the file containing potential passwords.
• <target>: Indicates the IP address or domain of the website.
• http-post-form: Indicates that the target is an HTTP form utilizing the POST method.
• /login.php:user=^USER^&pass=^PASS^: Specifies the login URL and the field names for username and password, which you should adjust to match the website’s form structure.
• F=incorrect: Denotes the error message displayed when the login attempt fails.

Example Command for an HTTP Login Form:

hydra -l admin -P passwords.txt example.com http-post-form "/login.php:user=^USER^&pass=^PASS^:F=Login failed"

In this example, Hydra will try to log in with the username admin using passwords from passwords.txt against the example.com website. The form uses user and pass as field names, while “Login failed” indicates an unsuccessful attempt.

Sample Output:

[DATA] attacking http-post-form://example.com/login.php:user=^USER^&pass=^PASS^:F=Login failed
[80][http-post-form] host: example.com   login: admin   password: 123456
[STATUS] attack finished for example.com (valid pair found)

Explanation:
The output reveals that Hydra successfully identified the correct password (123456) for the admin account. It lists the host (example.com), the login attempt, and the corresponding password that succeeded.

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Brute Force Attacks on HTTPS Forms

When targeting HTTPS login forms, the command structure remains largely the same, but you specify https-post-form instead of http-post-form. Here’s the command for attacking an HTTPS login form:

hydra -l <username> -P <password_list> <target> https-post-form "/login.php:user=^USER^&pass=^PASS^:F=Login failed"

Command for HTTPS Login Form

hydra -l admin -P passwords.txt secure-example.com https-post-form "/login.php:user=^USER^&pass=^PASS^:F=Login failed"

Hydra will attempt to crack the login form at secure-example.com using the specified username (admin) and passwords from passwords.txt.

Sample Output:

[DATA] attacking https-post-form://secure-example.com/login.php:user=^USER^&pass=^PASS^:F=Login failed
[443][https-post-form] host: secure-example.com   login: admin   password: letmein
[STATUS] attack finished for secure-example.com (valid pair found)

Explanation:
In this output, Hydra has successfully found the password letmein for the admin account on an HTTPS-protected website.

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Creating a Password List for Brute Force Attacks

For effective brute force attacks, Hydra requires a password list (wordlist) containing potential passwords. You can download pre-made wordlists, such as those found in the SecLists project, or create a simple one for your testing.

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Ethical Considerations and Security Best Practices

Engaging in brute force attacks without permission is illegal and unethical. Always ensure you have explicit consent to test the security of any web application. Hydra is a tool meant for ethical hacking and penetration testing, and it should only be employed in environments where you have authorization.

How to Defend Against Brute Force Attacks

Knowing how to attack is half the battle. The other half — arguably more important — is learning how to defend against those same attacks. Whether you’re a developer or security enthusiast, these practices are essential.

1. Rate Limiting & Account Lockouts

Don’t let attackers try unlimited combinations. Enforce:

• Rate limiting – only allow X login attempts per IP per minute.
• Temporary account lockouts – after 3–5 failed attempts, lock the account for a short period.

2. Use CAPTCHA

CAPTCHAs make automation difficult for brute force tools like Hydra. Tools exist to bypass them, but it significantly raises the difficulty level for the attacker.

3. Multi-Factor Authentication (MFA)

Even if the attacker gets a valid username and password, MFA adds another wall. An SMS code, authenticator app, or biometrics can shut down most brute force attempts cold.

4. Password Hygiene and User Education

Encourage strong passwords and offer a password strength meter on your registration form. Educating users is the first line of defense.

5. Monitoring and Logging

Use fail2ban, intrusion detection systems (IDS), or even basic log analysis to monitor failed login attempts. Alerting on abnormal patterns helps you act before damage is done.

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Fortify Your Web Security Arsenal

Brute force attacks remain a prevalent threat in the cybersecurity landscape. By mastering tools like Hydra in Termux, ethical hackers and developers can proactively identify and mitigate potential vulnerabilities in web applications. Remember, with great power comes great responsibility. Always ensure you have proper authorization before testing any system.​

For more in-depth tutorials and the latest in ethical hacking techniques, subscribe to my newsletter: https://www.samgalope.dev/newsletter/

⚠️ Important: These tools are intended for ethical hacking, security research, and education. Use them only on systems and networks you own or have permission to test. Unauthorized use can lead to serious legal consequences.