Brute force attacks stand out among the different cyberattack types because they’re relatively simple and bring the potential for severe consequences.
They’ve been around for decades, but continue to be a favorite method for hackers, especially when the target(s) use weak password security.
In this article, we dive into what they are, how they work, why they’re effective, and how you can protect yourself and your organization from becoming their victim.
What is a Brute Force Attack?
It’s a method cybercriminals use to gain unauthorized access to systems by guessing login credentials like usernames and passwords through a process of trial and error.
Unlike cyberattacks like trojans or zero-day exploits that focus on vulnerabilities in software or hardware, brute force attacks don’t rely on system flaws. They exploit the fact that many users choose passwords that are weak or easy to guess.
Brute force attacks are all about persistence. Attackers input a large amount of potential password combinations hoping to eventually find the correct one. With enough computational power and time, brute force attacks can break into nearly any system if it’s not properly defended.
The rise of automation and advancements in computing resources make these attacks easier to execute and more difficult to defend against.
How Do Brute Force Attacks Work?
Brute force attacks take several forms, each with varying levels of sophistication. These are some of the most common types.
Simple Brute Force Attack
This is the most basic form. The attacker tries every possible combination of characters to find the correct password. If the password is a simple 4-digit PIN, the attacker attempts all combinations from 0000 to 9999.
Dictionary Attack
In dictionary attacks the bad actor uses a precompiled list of common passwords, referred to as a “dictionary.” They aggregate these lists from previous passwords leaks or from common password patterns that many users rely on.
They’re faster than a simple brute force attack because it focuses on commonly used passwords instead of trying every possible combination.
Hybrid Attack
This method combines elements of brute force and dictionary attacks. The attacker starts with a dictionary of common passwords but adds variations such as appending numbers or symbols to increase the chances of success.
Credential Stuffing
When attackers get their hands on a list of stolen login credentials from a compromise like a data breach, they use them to attempt to log in to other accounts. A lot of people reuse passwords across multiple applications and portals, so this method can be highly effective.
Why Are Brute Force Attacks Effective?
There are multiple reasons brute force attacks continue to be effective.
Weak Passwords
Simple passwords like “password123” or “abcd1234” are all too common because they’re easy to remember. But if a password is easy to remember, it’s easy for attackers to guess.
Reusing Passwords
It’s common for users to reuse the same password across multiple websites. If one site is compromised, the attacker can use the stolen credentials to try accessing other accounts like email or banking services through credential stuffing.
No Dual or Multi-Factor Authentication
A lot of systems still rely on passwords as the only means of authentication. Without additional security layers like dual and multi-factor authentication they’re far more vulnerable to brute force attacks.
Automated Tools and High Computational Power
Attackers use automated tools like Hydra, John the Ripper, or Aircrack-ng to speed up the process. These tools attempt thousands of password combinations per second. With modern computers and cloud-based services, attackers have access to enormous computational resources to power malicious automated tools.
The Consequences of a Successful Brute Force Attack
When a brute force attack is successful, the consequences can be devastating. Here are a few real-world examples that illustrate the impact:
Yahoo Breach
In one of the largest breaches in history, Yahoo was compromised, and the personal information of over 3 billion users was exposed. A significant portion of this breach involved brute force attacks, where attackers exploited weak security measures and poor password practices.
- LinkedIn Data Leak: LinkedIn suffered a massive data breach in 2012, which resulted in millions of user credentials being exposed. Hackers then used brute force and dictionary attacks to decrypt weakly hashed passwords, leading to further security breaches across other platforms.
- Credential Stuffing Attacks on Banks: Numerous financial institutions have been targeted by credential stuffing attacks, where attackers used stolen login credentials to gain access to users’ accounts. In many cases, the attackers succeeded due to the victims reusing passwords across different services.
How to Prevent Brute Force Attacks
This type of cyber attack is persistent, so it’s crucial to implement a defense in depth cybersecurity strategy.
Here are several effective ways to do that:
Strong Password Policies
Users need to create complex passwords. Recommended length is at least 12-16 characters long with a mix of letters, numbers, and symbols. Passwords shouldn’t contain information that’s easy to guess like the user’s name, birthdate, or common phrases.
Multi-Factor Authentication (MFA)
One of the most effective defenses against brute force attacks is to enable MFA. This adds an additional layer of security that requires a second form of verification beyond a password.
Even if an attacker manages to guess the password, they’ll still be blocked from accessing the account without access to the second factor.
Account Lockout Mechanisms
Implementing an account lockout policy, where an account is temporarily locked after a certain number of failed login attempts, significantly slows down or stops brute force attacks.
For example, locking an account for 10 minutes after X amount of failed login attempts forces the attacker to wait or focus on a different target.
CAPTCHAs and Rate Limiting
CAPTCHAs distinguish human users from automated bots. Rate limiting restricts the number of login attempts from a specific IP address within a specified time frame. This makes it more difficult for attackers to conduct brute force attacks at scale.
Password Hashing and Salting
Systems should use secure hashing algorithms for storing passwords. Used in conjunction with salting this ensures that even if the password database is compromised the attacker can’t easily reverse the hashed passwords.
The Future of Brute Force Attacks
As technology evolves, so do the methods used by bad actors. It’s common for artificial intelligence (AI) and machine learning (ML) to play a role in this type of cyber attack. These technologies optimize the password-guessing process, making it faster and more accurate.
Quantum computing also presents a future challenge. While today’s cryptographic techniques are secure against traditional brute force methods, quantum computers have the potential to break modern encryption much faster. This would make current password protections obsolete, requiring the development of new security protocols and frameworks.
On the defense side, advancements in biometric authentication like facial recognition or fingerprint scanning, may reduce the reliance on passwords altogether. Similarly, blockchain technology enables more secure and decentralized authentication systems.
Conclusion
Brute force attacks are a common threat in cybersecurity. They’re fairly simple to pull off, and combined with modern computational power, makes them a formidable method for cybercriminals.
With strong password policies, multi-factor authentication, and modern defense techniques, individuals and organizations can greatly reduce the risk of falling victim to brute force attacks.
As the cybersecurity landscape continues to evolve, staying vigilant and up to date on best practices is critical for staying secure.
