A brute force attack is a trial-and-error method of finding the correct login credentials. Hackers will ‘force’ multiple combinations of usernames and passwords until they find an authentic login credential. This common cyberattack requires organizations to implement protective measures for their networks and accounts to prevent unauthorized access.

A brute force attack occurs when someone attempts to break into accounts by repeatedly guessing the password. Think of it like someone trying every possible combination on a lock until it finally opens.

Attackers use computer programs that can automatically try thousands of different username and password combinations very quickly, working non-stop until they find the right one that gains them access to an account. Once they break in, they can steal personal information, money, or use your account to attack others. The tactic is cheap, fast, and often successful. This is why every organization needs a plan to stop brute force attacks before they open the door to data theft, ransomware, and account takeovers.

Modern brute force attacks use automated software that can attempt thousands of logins per minute. These tools cycle through pre-built password lists or generate combinations, testing each credential against target systems. The automated nature of these allows attackers to test millions of potential passwords in a short timeframe.

The password complexity and uniqueness directly influence the success of brute force attacks. Simple passwords, such as "admin," can be easily cracked within seconds, while more complex ones require exponentially more time and resources to break. This is why attackers often target systems with weak security policies or predictable password patterns.

These attacks are also highly scalable. Once set up, brute force tools can simultaneously test credentials across hundreds or thousands of systems, increasing the likelihood of success. Additionally, they can run continuously without requiring constant supervision from the attacker.

Lastly, brute force attacks capitalize on predictable human behavior. Users often choose weak passwords, reuse credentials, or fail to implement strong security practices. This behavior makes brute force attacks effective.

If successful, brute force attacks can provide cybercriminals with the initial access needed for further malicious activity. Once authentication credentials are compromised, attackers gain persistent access to systems, allowing them to conduct reconnaissance, exfiltrate data, deploy ransomware, move laterally within the network, and escalate privileges.

Account takeovers can also enable attackers to impersonate legitimate users and launch social engineering campaigns within the organization. Additionally, compromised credentials can lead to domain redirection, phishing infrastructure setups, and other types of malicious activity.

The speed of brute force attacks poses a unique challenge for defenders. While complex passwords may take years to crack, weak passwords are often compromised in seconds. This rapid timeline can outpace the detection and response capabilities of security systems, allowing attackers to establish a foothold before defenses can react.

Modern brute force attacks have evolved far beyond simple password guessing. Today's cybercriminals employ six distinct methods, each designed to exploit specific weaknesses in password security and user behavior.

Let’s look at the six brute force attack techniques:

Simple brute force attacks involve manual or automated attempts that cycle through every possible password combination, typically starting with obvious choices such as "password" or company names. These attacks exploit human tendencies toward predictable password creation patterns.

Attackers begin with high-probability targets, including the organization's name, common default passwords, and easily guessed combinations. The top five stolen passwords in 2025 were '123456', 'admin', '12345678', 'password', and 'Password', indicating that users continue to select predictable credentials despite security awareness efforts.

When conducted manually, attackers often incorporate basic reconnaissance, gathering personal information from social media profiles to construct likely password combinations using favorite sports teams, family member names, or significant dates.

Dictionary attacks employ automated scripts that test predefined lists of common words, phrases, and previously leaked passwords against target usernames. While not purely brute force in nature, these attacks often serve as precursors to more sophisticated methods.

The attack methodology involves systematically testing dictionary entries while applying common modification patterns. Base words undergo systematic variations including capitalization changes, numerical additions, and special character substitutions. This approach proves effective against users who believe simple modifications to common words provide adequate security.

Hybrid brute force attacks are a combination of dictionary attack methodologies merged with traditional brute force techniques. These attacks target passwords that blend standard terms with numbers or special characters, such as "SanDiego123" or "Rover2020."

After identifying potential base words through dictionary testing, the hybrid approach systematically applies character modifications, year additions, and special character combinations. This method effectively compromises passwords that users consider secure due to their word-plus-modification structure.

Password spraying is a tactical inversion of traditional brute force methods. In this method, instead of testing multiple passwords against individual accounts, attackers apply a single common password across extensive username databases. Common weak passwords like "Welcome123" are systematically tested against large user populations.

This approach proves particularly effective because it exploits organizational password policies and human behavioral patterns. IT departments often implement similar default passwords across systems, and users frequently select identical weak passwords across different platforms. The FBI has specifically highlighted password spraying due to its increasing prevalence and effectiveness against enterprise targets.

Password spraying also presents detection challenges, as individual accounts experience only limited login attempts, often remaining below security monitoring thresholds.

Credential stuffing is a technique used by cybercriminals that exploits the widespread practice of password reuse across multiple platforms. Cybercriminals systematically apply previously stolen username-password pairs against additional services, capitalizing on users' tendency to maintain consistent credentials across platforms.

The attack methodology involves collecting credential pairs from historical data breaches and systematically testing them against target platforms. When users maintain identical login credentials across multiple email, social media, banking, and professional accounts, a single compromised database can provide access to all of these systems.

Rainbow table attacks utilize precomputed tables of hashed passwords to accelerate password cracking processes. When organizations improperly store password hashes without adequate salting mechanisms, attackers can use these prebuilt lookup tables to identify the original plaintext passwords rapidly.

A rainbow table serves as a comprehensive database that maps password hashes to their corresponding plaintext values. Rather than computing hashes during attack execution, criminals reference precomputed results, dramatically reducing the time required for password recovery. This method proves most effective against systems implementing insufficient hash salting practices, where identical passwords produce identical hash values.

These six attack vectors demonstrate how cybercriminals have systematically adapted their methods to exploit both technological vulnerabilities and human behavior patterns. What began as simple password guessing has evolved into a sophisticated ecosystem of automated tools and techniques that capitalize on predictable security weaknesses. The effectiveness of these methods stems not from advanced technical complexity, but from their ability to exploit fundamental flaws in how organizations and individuals approach password security.

Brute force attacks succeed against weak passwords–both at the user and organizational level. The first step to preventing a successful brute force attack is to educate employees on the importance of a strong password. You should enforce policies to ensure employees are using robust passwords for their accounts. For example, you may require:

• Minimum character lengths with varied characters: Longer passwords with multiple character types are more difficult for a criminal to hack and could give your company time to respond to suspicious login activity. They’ll stump a simple brute force attack, and can significantly slow down a dictionary attack.

• Multi-word passwords: One of the best ways to beat dictionary attacks is to use passwords with multiple words instead of a single word. Adding numerals or symbols will add to the complexity and keep your account more secure.

• Avoid frequently used passwords: Make sure your employees know common passwords like "password" or "123456" are easier for criminals to hack. Ensure they are using passwords that are unique to them and don’t include their usernames.

• Use a different password and change them regularly: Credential stuffing works when people use the same login credentials for multiple accounts. You can avoid this scenario by requiring different passwords for their accounts, with required updates.

While it's important to have employees on the same page about password security, organizations need to take it a step further and implement security protocols to protect against cybercriminal activity. Besides employee security training and increasing password complexity, these organizational implements can stop brute force attacks:

• Multi-factor authentication: Requiring users to verify their identity twice can stop many brute force attacks. Besides having the correct login credentials, they will also need to provide a second authentication code. This can be delivered to the person via text message, phone call, authenticator app, or token. Alternatively, they may also need to answer a question only the account owner would know or provide their biometrics.

• Limited login attempts: Brute force attacks often rely on using a login page multiple times to attempt to authenticate login credentials. Organizations can configure their settings to lockout an account after a certain number of attempted login attempts. This could cause a significant delay and force hackers to move on to different targets.

• Password manager: Employees often use simple passwords out of convenience. If your organization provides an effective password manager that can generate and store strong passwords, this mitigates the convenience factor.

• Captcha: Captcha tools ask people to verify they are human and not robots. People will need to accomplish a task like identifying objects in a picture, clicking a checkmark, or retyping text. This extra step could stop automated brute force attacks from succeeding.

• Penetration testing: Organizations should conduct a penetration test to check their company for weak passwords or security vulnerabilities.

Organizations should have a framework in place to detect suspicious activity within their network. Detecting an account takeover–internal or external–prevents potentially enormous damage to your organization.

For example, if a vendor account is compromised through brute force, criminals can launch supply chain attacks that appear to be trusted email or portal activity. Behavioral AI flags unusual tone, geography, and financial requests, automatically blocking messages that originate from newly compromised accounts, even when the correct username and password were used.

Ready to see how Abnormal can detect and stop brute force–enabled email threats before they reach your users? Request a demo today and take the next step toward comprehensive protection.