Brute Force Attacks Explained: Types, Techniques, and Prevention

What is a brute force attack? 

A brute force attack is a method used by cybercriminals to gain unauthorized access to a system, account, or network by systematically guessing passwords or encryption keys. This type of attack relies on the trial-and-error approach where attackers try every possible combination of characters until the correct one is found. 

Many modern security systems implement rate limiting, account lockout mechanisms, or CAPTCHA protections to make brute force attacks far less effective. However, these attacks can still succeed against weak passwords or poorly secured systems that lack proper defenses. 

Brute force attacks can be directed at various targets, including online accounts and encrypted data. By using automated tools, cyber attackers can expedite the guessing process, making brute force attacks a persistent threat to individuals and organizations. 

This is part of a series of articles about zero trust security.

How brute force attacks work 

Brute force attacks repeatedly attempt different combinations of usernames and passwords until finding the correct one. Attackers use automated software tools to accelerate this guessing process, enabling them to try thousands—or even millions—of combinations in a short amount of time. The speed of these tools makes brute force attacks particularly dangerous.

These attacks can target both online and offline systems. Online brute force attacks involve repeatedly submitting login attempts over the internet, which may trigger account lockouts or IP blocking on systems with security controls. 

Offline brute force attacks are typically performed on stolen data files, such as encrypted password databases, where attackers can work without restrictions on the number of attempts. This makes offline attacks especially difficult to detect until a breach has already occurred.

One of the primary factors determining the success of brute force attacks is password complexity. Short, simple, or common passwords are significantly easier to crack than long, complex ones. Even with advanced brute force tools, attackers often require significant computational resources to crack well-designed passwords.

Motivations behind brute force attacks

Stealing personal data

Cybercriminals use this technique to gain access to personal accounts, accessing sensitive information like financial details, personal identification numbers, and private communications. Once accessed, this data can be sold on the dark web or used for identity theft and other fraudulent activities. The extraction of personal data is a lucrative business for cybercriminals, who capitalize on weak security measures. 

Spreading malware

Brute force attacks also serve as a vector for spreading malware. Once attackers gain access to a system through successful password cracking, they can install malicious software to disrupt operations or extract further data. Malware can propagate across networks, causing significant damage or enabling additional attacks such as ransomware.

Hijacking systems

Once cyber attackers control a system, they can manipulate its functions, intercept communication, or launch further attacks from the compromised host. System hijacking can lead to unauthorized access to critical infrastructure or sensitive organizational data.

Damaging reputation

Brute force attacks can damage an organization’s reputation. Public breaches, especially those involving customer data, can erode trust and harm a company’s brand. Attackers may use these methods to deface websites, leak confidential data, or disrupt services, negatively affecting public perception and customer loyalty.

Types of brute force attacks 

Simple brute force attacks

Simple brute force attacks involve guessing passwords without any known information about user credentials. The attacker attempts all possible password combinations using an automated script or tool. While this method is exhaustive, its effectiveness decreases with longer and more complex passwords. 

Success rates for this method are lower compared to more sophisticated techniques because it requires checking each possible combination. However, simple brute force can yield results given sufficient time and weak passwords. Hackers may use increased computing power and botnets to execute these attacks more rapidly. 

Dictionary attacks

Dictionary attacks, a subset of brute force techniques, use a list of likely passwords or phrases instead of random combinations. This list, often called a “dictionary,” includes common passwords, phrases, and their variations. Attackers use these dictionaries to quickly identify potential matches, speeding up the attack process compared to simple brute force.

Dictionary attacks can exploit predictable user behavior, as many people use weak or commonly used passwords. Using words or combinations from dictionaries for passwords increases vulnerability. 

Hybrid brute force attacks

Hybrid brute force attacks combine aspects of simple and dictionary attacks. They start with dictionary words and append numbers or symbols to create more variations, making it effective against passwords that incorporate predictable modifications. 

This method leverages common user behavior of adding characters to simple passwords to meet complexity requirements while maintaining memorability. Hybrid attacks pose risks when using minor variations of common passwords. Hackers can exploit these patterns with relative ease, because users fail to create passwords with truly random and unique characteristics.

Reverse brute force attacks

Reverse brute force attacks invert the typical order by starting with a known password and trying it against various usernames or accounts. This approach is useful in environments where the attacker has access to a list of common passwords but lacks specific username credentials. 

It targets systems where identical or weak passwords are reused across multiple users. The success of reverse attacks depends on the attacker’s ability to determine which accounts match the common passwords. 

Credential stuffing

Credential stuffing is similar to brute force attacks but differs in method. Unlike traditional brute force attacks that systematically guess passwords, credential stuffing exploits known username-password pairs from data breaches. While both involve automated login attempts, credential stuffing relies on credential reuse rather than pure trial-and-error guessing.

Best practices to prevent brute force attacks 

Both individuals and organizations are responsible for ensuring security in the face of brute force attacks. Here are some of the ways to help thwart these attacks.

1. Use complex and unique passwords

Complex, unique passwords are the first line of defense against brute force attacks. Passwords should be long and comprise random letters, numbers, and symbols, making it difficult for attackers to guess or use precompiled lists. Avoiding common phrases or easily deducible information enhances this layer of security.

Organizations can encourage such practices by implementing systems that reject weak or previously compromised passwords. Educating users on creating strong passwords and the use of password managers simplifies maintaining password integrity across numerous accounts. 

2. Employ Multi-Factor Authentication (MFA)

MFA provides an additional defense layer against brute force attacks. By requiring factors beyond a password, such as biometric data or time-sensitive codes, MFA complicates unauthorized access attempts. Compromising multiple authentication factors presents a significant challenge for attackers.

Organizations should mandate MFA for accessing sensitive or critical systems, ensuring stronger protection against credential-based threats. Communicating the importance and implementation of MFA to all users reinforces organizational security and protects data integrity, drastically reducing brute force attack success probabilities.

3. Regularly monitor and log access attempts

Regular monitoring and logging of access attempts are vital components for identifying and responding to brute force attacks. Such practices enable the timely detection of unauthorized attempts, allowing for quick action before successful breaches occur. Comprehensive logs provide insights into attack patterns and potential system vulnerabilities.

Implementing real-time monitoring systems that flag anomalies enables immediate investigation and response. Logging provides accountability and forensic insight, essential for post-incident analysis and future defense improvement. 

4. Implement password hashing and salting

Password hashing and salting are effective countermeasures against offline brute force attacks. Hashing transforms plaintext passwords into fixed-length strings using cryptographic functions. Salting adds random data to passwords before hashing, ensuring unique outputs even for identical passwords across the database.

These techniques prevent attackers from easily retrieving passwords from compromised databases, as hashes without salts can be susceptible to precomputed attack scripts. Adopting strong cryptographic hashing algorithms with unique salts for each password provides a formidable challenge to attackers attempting to execute offline brute force methods.

5. Educate users on security awareness

Users’ security awareness is also important in defending against brute force attacks. By informing users about the risks associated with weak passwords and teaching best security practices, the potential for successful attacks diminishes. Knowledgeable users are less likely to fall victim to related techniques such as phishing.

Security awareness programs should cover the importance of strong passwords, recognizing suspicious activity, and safe online behavior. Promoting the use of password managers and enabling MFA increases individual and organizational security. 

Preventing brute force attacks with Frontegg

Brute force attacks remain a persistent threat, but organizations don’t have to fight them alone. Frontegg’s customer identity and access management (CIAM) platform provides built-in security features that help mitigate these attacks without adding developer overhead. With adaptive authentication, MFA, role-based access controls (RBAC), and credential stuffing protection, Frontegg ensures that only legitimate users can access your systems—while keeping bad actors out.

By reducing reliance on developers and empowering security and product teams to enforce identity policies, Frontegg helps organizations stay secure, compliant, and agile. Instead of building authentication defenses from scratch, let Frontegg handle identity security—so your team can focus on innovation.

Ready to strengthen your defenses? Contact sales today.