26 Jan, 2023

Bruteforce

Vulnerability Assessment as a Service (VAaaS)

Tests systems and applications for vulnerabilities to address weaknesses.

The abbreviation of “Bruteforce” is often simply “BF” or “B/F”.

In the field of cybersecurity, “Bruteforce” refers to a method of breaking into a computer system or network by trying every possible combination of characters or words in a password or encryption key. This method is often used by hackers or cybercriminals to gain unauthorized access to a system. The term “brute force” is used to describe this method because it relies on raw computational power to try every possible combination, rather than using a more clever or efficient approach.

Brute force attacks can take many forms, such as dictionary attacks, which try every word in a dictionary as a possible password, or permutation attacks, which try every possible combination of characters in a password. These attacks can be automated and run through software programs known as “password cracking” or “password cracking tools” that can test thousands of possible passwords per second.

To prevent brute force attacks, security measures such as strong password policies, two-factor authentication, and rate limiting can be used. Additionally, intrusion detection systems and firewalls can be used to detect and block repeated login attempts, which is a common tactic used in brute force attacks.

Example of vulnerable code on different programming languages:

PHP:

				
					<?php
if(isset($_POST['username']) && isset($_POST['password'])) {
    $username = $_POST['username'];
    $password = $_POST['password'];
    if($username == "admin" && $password == "password") {
        echo "Welcome, admin!";
    } else {
        echo "Invalid username or password!";
    }
}
				
			

Python:

				
					if request.method == 'POST':
    username = request.form['username']
    password = request.form['password']
    if username == 'admin' and password == 'password':
        return "Welcome, admin!"
    else:
        return "Invalid username or password!"

				
			

Java

				
					if(username.equals("admin") && password.equals("password")) {
    System.out.println("Welcome, admin!");
} else {
    System.out.println("Invalid username or password!");
}
				
			

It should be noted that this code is just an example, and it is not recommended to use this type of authentication system in a production environment because it is vulnerable to brute force attacks.

Please be aware that the aforementioned code is only meant to serve as an illustration of how a brute force attack can potentially be used to gain unauthorized access to a system; it is not suggested as a method of authentication.

In practice, it’s crucial to employ rate limiting or lockout measures to stop continuous login attempts and secure authentication techniques like bcrypt or scrypt for password hashing.

Examples of exploitation Bruteforce

1.  Dictionary Attack: In this method, the attacker uses a pre-compiled list of words (i.e., a dictionary) as the possible passwords. The attacker runs through the list, trying each word as a password until the correct one is found.

2. Permutation Attack: In this method, the attacker uses a software program to generate all possible combinations of characters in a password. This can be very time-consuming, but it is also very effective if the password is not complex.

3. SSH Brute Force: SSH is a commonly used protocol for remote access to servers. An attacker can launch a brute force attack against SSH by repeatedly trying different username and password combinations in order to gain access to a server.

4. Distributed Brute Force Attack: In this method, the attacker uses a botnet, which is a group of infected computers, to launch the attack simultaneously from multiple locations. This makes it more difficult for the targeted system to detect and block the attack.

5. Brute force attack on web-based forms: In this method, the attacker uses automated scripts to repeatedly try different username and password combinations on a web-based login form in order to gain unauthorized access.

Brute force assaults are a common tactic used by hackers and cybercriminals despite the fact that they can be time-consuming and may not be effective. They are also fairly simple to start and can be automated.

Privilege escalation techniques.

Escalating privileges refers to the process of gaining increased access or permissions within a computer system or network. There are several methods that can be used to escalate privileges, including:

  • Exploiting vulnerabilities: This involves identifying and exploiting vulnerabilities in software or systems in order to gain elevated privileges. This can include using known exploits or writing custom code to take advantage of a vulnerability.

  • Social engineering: This involves tricking or manipulating users into giving up their login credentials or other sensitive information.

  • Password cracking: This involves using tools or techniques to gain access to an account by guessing or cracking the password.

  • Using default or weak passwords: This involves exploiting weak or easily guessable passwords in order to gain access to an account or system.

  • DLL injection: This is a technique that allows an attacker to execute arbitrary code in the context of another process by injecting a dynamic-link library (DLL) into the process’s address space.

  • Exploiting privilege escalation bugs: This is a method of exploiting a bug in an application or system that allows an attacker to gain elevated privileges.

  • Using built-in or third-party tools: This method involves using built-in or third-party tools like Metasploit, SET or PowerSploit etc to perform privilege escalation.

It should be noted that many of these methods require a significant level of technical knowledge and skill, and that many organizations have security measures in place to prevent or detect attempts to escalate privileges.

Methodology and checklist on testing for Bruteforce

Methodology:

  1. Preparation: Define the scope of the testing and the systems and applications that will be tested. Make sure that you have the necessary permissions and that you understand the testing guidelines and limitations.

  2. Information gathering: Gather information about the systems and applications that you will be testing. This can include researching known vulnerabilities, examining the source code, and studying the network architecture and configuration.

  3. Testing setup: Set up a testing environment that mimics the target environment as closely as possible. This can include creating virtual machines, installing the necessary software, and configuring the network.

  4. Brute force testing: Use automated tools or write custom scripts to simulate brute force attacks on the systems and applications being tested. The tools should be configured to try multiple combinations of characters and to track the number of attempts made.

  5. Data analysis: Analyze the results of the testing, including the number of login attempts, the time required to crack the password, and the success rate of the attack.

  6. Reporting: Prepare a report that summarizes the results of the testing and provides recommendations for improving the security of the systems and applications. The report should include a description of the testing methodology, a list of the systems and applications tested, the results of the testing, and any recommendations for improvement.

  7. Remediation: Implement the recommended changes and retest the systems and applications to verify that they are now secure against brute force attacks.

Checklist:

  • Password policy: Ensure that your password policy enforces strong passwords with a minimum length, a mix of upper and lower case letters, numbers, and special characters.

  • Rate limiting: Implement rate limiting to limit the number of login attempts from a single IP address in a given time period.

  • Two-factor authentication: Implement two-factor authentication to add an additional layer of security to your login process.

  • Lockout policy: Implement a lockout policy that temporarily or permanently locks out an account after a certain number of failed login attempts.

  • Honeypots: Use honeypots to lure attackers away from your real systems and onto fake systems that you control.

  • Logging and monitoring: Implement logging and monitoring to track login attempts, both successful and unsuccessful, and to alert you to potential brute force attacks.

  • Regular software updates: Regularly update your software and keep it up to date with the latest security patches to protect against known vulnerabilities.

  • Security awareness training: Provide security awareness training to your users to educate them on the importance of strong passwords and good security practices.

Software for Bruteforce attack

Automated Tools:

  • Hydra – A fast and flexible network login cracker that supports many protocols, including HTTP, FTP, SMTP, and more.

  • John the Ripper – A fast password cracker that supports many operating systems, including Windows, Linux, and macOS.

  • Ncrack – A network authentication cracking tool that supports a wide range of protocols, including RDP, SSH, and Telnet.

  • Metasploit Framework – A popular open-source penetration testing framework that includes modules for brute forcing passwords and cracking hashes.

  • Aircrack-ng – A wireless security testing tool that can be used to crack Wi-Fi passwords using brute force or dictionary attacks.

  • THC-Hydra – A fast and flexible network login cracker that supports many protocols, including HTTP, FTP, SMTP, and more.

  • Cain & Abel – A password recovery tool for Windows that supports many different cracking methods, including brute force.

  • Ophcrack – A free Windows password cracker that uses rainbow tables to crack LM and NTLM hashes.

  • Brutus – A free and easy-to-use brute force password cracking tool for Windows.

  • Fern WiFi Cracker – A GUI-based wireless security testing tool that can be used to crack Wi-Fi passwords using brute force or dictionary attacks.

Manual Tools:

  • Telnet – A simple and widely available protocol that can be used to brute force Telnet logins.

  • FTP – A widely used protocol that can be used to brute force FTP logins.

  • SSH – A secure shell protocol that can be used to brute force SSH logins.

  • RDP – A remote desktop protocol that can be used to brute force RDP logins.

  • HTTP – A widely used protocol that can be used to brute force HTTP logins, such as those found on web-based forms.

  • SMTP – A protocol used for sending email that can be used to brute force SMTP logins.

  • POP3 – A protocol used for receiving email that can be used to brute force POP3 logins.

  • IMAP – A protocol used for accessing email that can be used to brute force IMAP logins.

  • LDAP – A protocol used for accessing directory services that can be used to brute force LDAP logins.

  • MySQL – A widely used database management system that can be used to brute force MySQL logins.

Browser Plugins:

  • Passware Kit – A browser plugin for Internet Explorer that can be used to recover lost passwords and passwords stored in web browsers.

  • LastPass – A password manager and form filler that can be used to securely store passwords and automatically log into websites.

  • Dashlane – A password manager and form filler that can be used to securely store passwords and automatically log into websites.

  • 1Password – A password manager and form filler that can be used to securely store passwords and automatically log into websites.

  • RoboForm – A password manager and form filler that can be used to securely store passwords and automatically log into websites.

Avarage CVSS score Bruteforce

The Common Vulnerability Scoring System (CVSS) is a standardized method for evaluating the severity of vulnerabilities. The CVSS score is a numerical value that ranges from 0 to 10, with 10 being the most severe.

The CVSS score for a brute force attack would depend on the specific scenario and the potential impact. A brute force attack on a login form that results in unauthorized access to a system could result in a higher CVSS score than a brute force attack on a login form that is unsuccessful.

In general, a brute force attack that results in unauthorized access to a system or sensitive information would likely result in a high CVSS score, such as 8.0 or above. This is because it is considered as a high severity attack that could lead to serious consequences, such as data loss or unauthorized access to sensitive information.

However, it should be noted that the CVSS score is based on a number of factors and can vary depending on the specific scenario. It’s important to consult the CVSS v3.1 standard for more accurate information.

CWE information about Bruteforce

The Common Weakness Enumeration (CWE) is a comprehensive and standardized list of software weaknesses that can be used by organizations and individuals to improve the security of their software systems. CWE is maintained by the MITRE Corporation and is used by the software security industry, including governments, businesses, and individual software developers.

Here are some of the CWEs related to brute force:

CWE-307: Improper Restriction of Excessive Authentication Attempts – This weakness occurs when an application does not properly restrict the number of authentication attempts, making it vulnerable to brute force attacks.

CWE-352: Cross-Site Request Forgery (CSRF) – This weakness can be exploited in combination with a brute force attack to bypass authentication mechanisms.

CWE-326: Inadequate Encryption Strength – If the encryption strength used to protect sensitive information is not strong enough, it can be vulnerable to brute force attacks.

CWE-311: Missing Encryption of Sensitive Data – This weakness occurs when sensitive data is not properly encrypted, making it vulnerable to brute force attacks.

CWE-259: Use of Hard-coded Password – The use of hard-coded passwords makes an application vulnerable to brute force attacks.

CWE-200: Information Exposure – This weakness can occur when an application does not properly secure its logs, making it possible for attackers to access sensitive information through brute force attacks.

CWE-297: Improper Password Storage – This weakness occurs when passwords are not properly stored, making them vulnerable to brute force attacks.

CWE-307: Improper Authentication – This weakness occurs when an application does not properly authenticate users, making it vulnerable to brute force attacks.

CWE-291: Reliance on a Broken or Risky Cryptographic Algorithm – This weakness can make an application vulnerable to brute force attacks if it relies on a weak or broken cryptographic algorithm.

Top CVES related to Bruteforce

CVES that are related to brute force attacks would typically be those that involve vulnerabilities in authentication or access controls. Here are a few examples of CVES that are related to brute force attacks:

CVE-2017-15361: A vulnerability in the authentication process of the Cisco Adaptive Security Appliance (ASA) software that could allow an attacker to launch a brute force attack against the device’s web interface.

CVE-2019-1010234: A vulnerability in the authentication process of the OpenSSH software that could allow an attacker to launch a brute force attack against the server.

CVE-2018-20250: A vulnerability in the authentication process of the Joomla! CMS that could allow an attacker to launch a brute force attack against the login page.

CVE-2017-14494: A vulnerability in the authentication process of the Jenkins Continuous Integration server that could allow an attacker to launch a brute force attack against the login page.

CVE-2018-1000861: A vulnerability in the authentication process of the Jenkins Continuous Integration server that could allow an attacker to launch a brute force attack against the login page.

It’s important to note that this is a small sample of CVES related to brute force attacks, and new vulnerabilities are constantly being discovered.

List of popular Bruteforce exploits

There are many ways to exploit a system or network that is vulnerable to a brute force attack. Here are a few examples of popular exploits that can be used in a brute force attack:

  • SSH bruteforce: This exploit targets the Secure Shell (SSH) protocol and uses a script to try multiple username and password combinations in an attempt to gain unauthorized access to a system.

  • RDP bruteforce: This exploit targets the Remote Desktop Protocol (RDP) and uses a script to try multiple username and password combinations in an attempt to gain unauthorized access to a system.

  • FTP bruteforce: This exploit targets the File Transfer Protocol (FTP) and uses a script to try multiple username and password combinations in an attempt to gain unauthorized access to a system.

  • Telnet bruteforce: This exploit targets the Telnet protocol and uses a script to try multiple username and password combinations in an attempt to gain unauthorized access to a system.

  • HTTP(S) bruteforce: This exploit targets the HTTP(S) protocol and uses a script to try multiple username and password combinations in an attempt to gain unauthorized access to a web application.

  • SMB bruteforce: This exploit targets the Server Message Block (SMB) protocol and uses a script to try multiple username and password combinations in an attempt to gain unauthorized access to a system.

  • VNC bruteforce: This exploit targets the Virtual Network Computing (VNC) protocol and uses a script to try multiple username and password combinations in an attempt to gain unauthorized access to a system.

Practicing in test for Bruteforce

If you are interested in learning about and practicing with brute force techniques, there are several options for you to consider:

  1. Setting up a personal lab environment: You can set up a virtual environment on your own computer where you can experiment with different types of brute force attacks and techniques.

  2. Participating in Capture the Flag (CTF) events: CTF events are a type of computer security competition that often include challenges related to brute force attacks. These events are a great way to learn and practice your skills in a controlled and legal environment.

  3. Using intentionally vulnerable systems: There are various intentionally vulnerable systems and applications that you can use to practice your brute force skills, such as Metasploitable, DVWA, and OWASP Juice Shop.

For study Bruteforce

  1. Courses: There are several online courses that cover brute force attacks and how to defend against them, such as “Ethical Hacking and Penetration Testing” on Udemy, “Brute Force Attack and Defense” on Coursera, and “Brute Force and Dictionary Attacks” on Pluralsight.

  2. Websites: There are several websites that provide resources and practice challenges to help improve your understanding of brute force attacks and how to defend against them, such as HackTheBox, VulnHub, and Root-Me.

  3. Videos: There are several YouTube channels and videos that cover the topic of brute force attacks and how to defend against them, such as “Brute Force Attack Tutorial” by Null Byte, “Brute Force Attack Prevention” by Hak5, and “Understanding Brute Force Attacks” by SANS Institute.

It’s important to note that the above-mentioned resources are just a small sample of the available resources, there are many other resources that can be used to learn about brute force attacks and how to defend against them.

Books with review of Bruteforce

  • “Black Hat Python: Python Programming for Hackers and Pentesters” by Justin Seitz: This book provides an in-depth look at how hackers use Python to launch brute force attacks, and also provides practical examples of how to write scripts to automate the process of launching these attacks.

  • “Violent Python: A Cookbook for Hackers, Forensic Analysts, Penetration Testers and Security Engineers” by TJ O’Connor: This book provides an overview of different types of brute force attacks, as well as a variety of tools and techniques that can be used to launch and defend against these attacks.

  • “Hacking: The Art of Exploitation” by Jon Erickson: This book provides a detailed look at how hackers use brute force attacks to gain unauthorized access to systems and networks. The book also provides practical examples and exercises to help readers understand the concepts.

  • “Professional Penetration Testing: Creating and Learning in a Hacking Lab” by Thomas Wilhelm: This book provides an in-depth look at the tools and techniques used in penetration testing, including brute force attacks. It also provides a detailed explanation of how to set up and use a hacking lab to practice and improve your skills.

  • “Brute Force: Cracking the Data Encryption Standard” by Matt Curtin: This book provides an in-depth look at the history and development of the Data Encryption Standard (DES) and how the algorithm was eventually broken by brute force methods.

How to be protected from Bruteforce

Here are some steps that can help protect against brute force attacks:

  1. Make sure to use strong and unique passwords for all of your accounts. This makes it more difficult for an attacker to guess your password and gain access to your account.

  2. Two-factor authentication (2FA) adds an extra layer of security to your accounts by requiring a second factor of authentication in addition to your password.

  3. Limit the number of login attempts that can be made to your accounts to prevent brute force attacks. After a certain number of failed login attempts, the account should be temporarily locked.

  4. Consider using a secure authentication method, such as public-key authentication, to access your accounts. This makes it more difficult for an attacker to gain access to your account.

  5. Keep your software and systems up-to-date to ensure that they are protected against the latest security vulnerabilities.

  6. Regularly monitor your systems and networks for any signs of a brute force attack. This includes monitoring log files, network traffic, and system resource usage.

  7. A web application firewall (WAF) can help protect against brute force attacks by monitoring incoming traffic and blocking malicious requests.

  8. Intrusion detection and prevention systems (ID/IPS) can help detect and prevent brute force attacks by monitoring network traffic and identifying patterns of malicious behavior.

Mitigations Bruteforce vulnerability

There are several mitigation methods that can be used to protect against Bruteforce:

  1. Implementing strong password policies: Requiring the use of complex, unique passwords can make it more difficult for an attacker to successfully launch a brute force attack.

  2. Enabling two-factor authentication: Two-factor authentication can make it more difficult for an attacker to gain access, even if they have the correct login credentials.

  3. Limiting login attempts: Implementing a limit on the number of login attempts that can be made before an account is locked or an IP is blocked can make it more difficult for an attacker to launch a brute force attack.

  4. Using intrusion detection systems: Intrusion detection systems can detect and alert on the signs of a brute force attack, which can help to quickly identify and respond to an attack.

  5. Keeping software updated: Keeping software up-to-date can help to ensure that known vulnerabilities are patched and that the latest security measures are in place.

  6. Using firewalls: Firewalls can be used to block IP addresses that are attempting to launch a brute force attack.

  7. Using security tools: There are several security tools that can help to detect and defend against brute force attacks, such as intrusion detection and prevention systems (IDPS), and security information and event management (SIEM) systems.

  8. Using CAPTCHA: Implementing CAPTCHA can prevent bots from launching a brute force attack, by requiring human intervention

Conclusion

Brute force is a method of breaking into a password-protected system or network by trying all possible combinations of characters, words, or phrases until the correct one is found. This method is commonly used by attackers to gain unauthorized access to systems and networks, and can also be used to crack encryption. It can be a slow process but with the advancement of technology and powerful hardware, it can be done in a faster way. To protect against brute force attacks, it’s important to use strong passwords, limit login attempts, and use intrusion detection systems, firewalls and security tools.

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