Brute Force Attack - Definition, Types & How It Works

Introduction

Ever logged into an account and gotten that dreaded "incorrect password" message? It happens to the best of us. But what if someone was behind those failed attempts, trying to crack your password and access your personal information?

That's where brute-force attacks come in – a type of cybercrime in which many attempts are made to hack into a website using different password combinations. Hackers attempt this by installing malicious bots on other systems to increase the power necessary for such assaults.

Understanding brute-force attacks is crucial whether you're running a business website or just protecting your social media accounts. In this guide, we'll explain exactly how they work, the different types you might encounter, and, most importantly, how to defend yourself and keep your online data secure. Keep reading!

What is a brute force attack?

A brute force attack involves an attacker using automated software or scripts to systematically guess login credentials by trying various combinations of characters, numbers, and symbols. The software will try different combinations until it eventually stumbles upon the correct username and password combination that grants access.

It's a method of cracking passwords through sheer trial-and-error and computational power rather than using more sophisticated techniques. The attacker relies on brute force, trying every possible combination until they get it right.

Brute force attacks can be effective against weak or simple passwords, but they become increasingly difficult and time-consuming as passwords become longer and more complex. However, with powerful computers and botnets (networks of compromised devices), attackers can significantly increase the number of guesses they can make per second, making brute-force attacks more feasible even against stronger passwords.

Importance of understanding brute force attacks

When a system is compromised through a brute force attack, it can be exploited as a mail server to distribute spam to countless victims. Understanding how brute force attacks work helps implement robust security measures to prevent unauthorised access, thus thwarting the hijacking of systems for spam distribution.

By securing systems against brute force attacks, the potential for spam distribution can be significantly reduced, preserving the integrity of communication channels and protecting users from unwanted or harmful content.

Also, understanding the tactics used in brute force attacks enables users to recognise potential vulnerabilities in their social media accounts and take proactive steps to secure them. By regularly updating passwords, enabling two-factor authentication, and monitoring account activity for suspicious behaviour, individuals can mitigate the risk of social media breaches and prevent disseminating malicious content to their connections.

Understanding brute force attacks
How does a brute force attack work?

A Brute Force Attack operates by systematically attempting various combinations of passwords or authentication credentials until the correct one is discovered. Attackers typically employ bots or automated tools programmed with a list of common passwords and login details. These tools then systematically input these combinations into the login interface of the target website or application.

Attackers may also manually guess login details from sources like the dark web or security breaches. However, manual guessing can be time-consuming, prompting attackers to rely on software or other brute-force tools to speed up the process. These tools enable attackers to rapidly generate and test multiple combinations of passwords, usernames, or session IDs to gain unauthorised access.

Key components involved in brute force attacks

The key components involved in brute force attacks are:

• Target system: The system or application that the attacker aims to compromise, such as a website, server, or database.
• Attack vector: The entry point or vulnerability that the attacker attempts to exploit, such as a login page, encryption algorithm, or authentication mechanism.
• Dictionary or wordlist: A pre-compiled list of common passwords, words, or character combinations that the attacker uses to generate potential solutions.
• Computing power: The computational resources available to the attacker, such as CPU processing power, memory, and storage capacity, which determine the speed and efficiency of the brute force attack.
• Network connectivity: The ability to establish and maintain a connection with the target system is essential for sending and receiving data during the attack process.

Why are brute force attacks effective?

Brute force attacks are highly effective due to their simplicity, automation capabilities, and cyber attack versatility. These attacks involve systematically trying all possible combinations of usernames, passwords, or encryption keys until the correct one is found. Also, they are a common tactic in the early stages of cyber intrusions, particularly during reconnaissance and invasion phases, where attackers seek initial access to target networks or systems.

Moreover, the automation capabilities of brute force attacks significantly enhance their effectiveness. Cybercriminals can easily automate these attacks to operate in parallel, enabling them to scale their efforts and increase their chances of success. This scalability allows attackers to cast a wide net, simultaneously targeting multiple potential entry points.

Types of brute force attacks

There are several types of brute force attacks, each with its approach and techniques. Here's an overview of the different types of brute force attacks:

• Simple brute force attack: This is the most basic type of brute force attack, where an attacker uses automation and scripts to guess passwords by trying every possible combination of characters. These attacks can make hundreds of guesses per second, and simple passwords can be cracked in minutes.

• Credential stuffing: This attack involves using stolen login credentials (usernames and passwords) from data breaches and attempting to access other accounts where users have reused their credentials.

• Hybrid brute force attack: This attack combines a dictionary and brute force attacks. It first uses a dictionary attack to provide common words, and then a brute force attack is used to guess the additional characters or numbers that users often add to their passwords.

• Botnets: Brute force attacks require significant computing power, and attackers often employ botnets (networks of hijacked computers) to execute the attack algorithm at a larger scale. 

Real-world examples of brute force attacks

Now that we've covered the fundamentals of brute force assaults, let's look at some examples of this dangerous cyber threat:

• Russian military targeting microsoft accounts (2020): In 2020, members of the Russian military reportedly used brute force attacks to target over 200 organisations, including advocacy groups, political parties, and consultants, to gain access to their Microsoft Office 365 accounts. The targets included institutions like the German Marshall Fund and the European People's Party.

• T-Mobile data breach (2021): A hacker used a combination of brute force attacks and other techniques to gain access to T-Mobile's servers, leading to a data breach that exposed the personal information of around 40 million customers. The stolen data was first offered for sale for 6 Bitcoins but was eventually sold for just $200.

• GitHub brute force attack (2013): In 2013, several GitHub users were victims of a brute force attack due to weak passwords. The attackers used nearly 40,000 individual IP addresses to carry out the attack gradually and avoid detection by GitHub's security systems. Affected users were required to update their passwords with stronger combinations.

How to detect brute force attacks?

Individuals and organisations can proactively identify and respond to brute-force attacks by recognising certain indicators. Here's how to detect a brute force attack:

• Unusual patterns of failed login attempts: Keep an eye out for a sudden increase in failed login attempts, especially if they follow a repetitive pattern or originate from multiple sources. Brute force attacks often involve systematic attempts to guess passwords, resulting in a high volume of failed login attempts within a short period.

• Logging in from an unusual IP address: Monitor login activity and avoid login attempts from unfamiliar or suspicious IP addresses. Brute force attackers may attempt to access systems from different locations to evade detection, so identifying logins from unusual IP addresses can indicate malicious activity.

• Unusual user behaviour: Pay attention to any unusual user behaviour, such as repeated password resets, changes in access patterns, or unauthorised attempts to escalate privileges. These anomalies could indicate an attacker attempting to gain unauthorised access through brute force.

• Increased internet use after login: Monitor network activity for any significant spikes in Internet usage following a login. Brute force attackers may use compromised systems to conduct malicious activities such as spam distribution, malware propagation, or data exfiltration, leading to increased network traffic.

Strategies for preventing brute force attacks

Brute force attacks are a persistent threat to online systems, and to mitigate this risk, you can implement various strategies. These include:

• Strong password policies: Enforce strong, unique, and complex passwords that are difficult to crack. Longer passwords with a mix of characters, numbers, and symbols significantly increase the complexity and make brute-force attacks more challenging.

• Account lockout mechanisms: Implement account lockout policies that temporarily block or suspend accounts after a certain number of failed login attempts. This prevents attackers from attempting an unlimited number of password guesses.

• Two-factor authentication: Implement an additional layer of security by requiring an extra authentication factor, such as a one-time OTP sent to a user's registered device or a hardware token. Even if the attacker obtains the password, they cannot access the account without the second factor.

• CAPTCHA implementation: Utilise CAPTCHA challenges on login pages to differentiate between human users and automated bots or scripts. CAPTCHAs can effectively prevent brute-force attacks conducted by automated tools.

• IP address restrictions: Limit access to sensitive areas, such as login pages or administrative interfaces, by whitelisting trusted IP addresses or IP ranges. This can prevent brute force attempts from untrusted or unauthorised sources.

• Monitoring and logging: Implement robust monitoring and logging mechanisms to detect and analyse potential brute force attempts. Detailed logs can help identify patterns, sources, and techniques attackers use, enabling proactive countermeasures.

Tools and resources for brute force attack mitigation

Penetration testing allows you to detect security flaws in your IT system by hacking it like a hacker would. Here are some of the top tools that you may utilise to mitigate the repercussions of a brute-force attack:

• BruteX: BruteX is an automated tool designed to brute-force various services running on the target system, including open ports, usernames, and passwords. Its integration with services like Nmap and Hydra enhances its functionality, making it a comprehensive option for penetration testing.
• Disreach: Disreach specialises in brute-forcing files and directories in web servers, offering features like request delaying, user-agent randomisation, and proxy support for thorough testing. Written in Python, it is compatible with Linux, Windows, and macOS, making it accessible across different platforms.
• Callow: Callow is a user-friendly brute force tool written in Python 3, offering customisation options and an intuitive user interface suitable for users of all levels. Its easy error-handling mechanism and open-source nature make it versatile for experimentation and testing.
• SSB (Secure Shell Bruteforcer): SSB prioritises brute-forcing SSH servers, offering a fast and intuitive solution with a high accuracy rate in detecting leaked databases and supporting popular accounts like Instagram and Gmail. It utilises the SSB secure shell to provide a secure interface for brute-force attacks.
• Burp Suite Professional: Burp Suite Professional is a versatile toolkit for web security testing, automating tasks and providing comprehensive reports on vulnerabilities. Experts widely use it to test the top ten vulnerabilities listed by OWASP, offering features like scan coverage increase, dark mode customisation, and out-of-band application security testing (OAST) for thorough analysis.

Future trends in brute force attack prevention

As the landscape of cyber threats evolves, it's crucial to anticipate future trends in brute force attacks and implement proactive measures to prevent them. Here are some strategies for mitigating emerging threats:

• Diversification of targets: With the increasing adoption of new technologies like IoT, smart home systems, and ICS, it's vital to bolster security measures for these systems. Implementing robust authentication protocols and encryption standards can help mitigate the risk of brute-force attacks targeting these emerging technologies.

• Behavioural analysis: Machine learning-based anomaly detection systems can be crucial in identifying anomalous login behaviours indicative of brute force attacks. By continuously analysing user behaviour and identifying deviations from normal patterns, organisations can enhance their ability to detect and respond to brute-force attacks in real time.

• Enhanced authentication: As MFA becomes increasingly prevalent, organisations should consider incorporating advanced biometrics, behavioural analysis, and continuous authentication to enhance the security of their authentication processes. By adopting a layered approach to authentication, organisations can reduce the likelihood of successful brute force attacks and strengthen overall cyber security posture.

Conclusion

During a brute force attack, attackers aim to exploit weaknesses in the authentication system and gain entry into the target system or network by continuously trying different combinations. This method allows attackers to bypass traditional security measures and access sensitive information or resources. Basically, brute force attacks leverage automation and systematic trial-and-error to breach security defences and compromise targeted systems or applications.