Brute Force vs Dictionary Attacks: How Do They Differ?

Brute force and dictionary attacks are two frequently used techniques that cybercriminals use to compromise passwords and gain unauthorized access to websites. While they share a common goal, their approaches and countermeasures vary significantly. This guide will explain the differences between both password attacks and offer guidance on preventing them.

An overview of brute force vs dictionary attacks

What are brute force attacks, and how do they work?

Brute force attacks are a method of trial and error used by cybercriminals to decode encrypted data such as passwords. This technique involves systematically checking all possible combinations until they find the correct one. 

Typically, brute force attacks begin with the simplest, most common passwords before progressing to more complex combinations. These attacks require significant computational power, as the number of combinations increases exponentially with password length and complexity.

What are dictionary attacks, and how do they work?

Dictionary attacks, on the other hand, are more refined. They use a file containing words, phrases, common passwords, and other likely combinations. Instead of trying every possible combination like brute force attacks, dictionary attacks use this pre-assembled list to guess passwords. 

This method is based on the tendency of many users to choose simple, common words or phrases, making dictionary attacks faster and less resource intensive compared to brute force attacks.

The differences between brute force and dictionary attacks

When discussing cybersecurity threats — particularly brute force and dictionary attacks — it’s important to understand their distinct characteristics. 

The upcoming sections will delve into these differences in detail, highlighting the unique aspects of each attack type.

1. Attack methodology

Brute force: Exhaustive trial and error

Brute force attacks are the epitome of persistence in cyberattacks. This method employs an exhaustive trial-and-error approach, systematically attempting every possible combination of characters until the correct password is discovered. 

The methodology is straightforward, but demanding in terms of computational resources. It starts with the most basic combinations, like sequential numbers or commonly used passwords, and progressively becomes more complex. 

The brute force attack doesn’t rely on ingenuity or exploitation of human psychology, but purely on the power of computation and the inevitability that the right password will inevitably be found. 

Dictionary: Predefined wordlists or patterns

Dictionary attacks are more sophisticated in their approach. These attacks use a predefined list of words, phrases, and commonly used passwords, which are often derived from dictionaries. 

This significantly reduces the number of attempts needed to crack a password. The methodology is based on the common human behavior of using memorable words or simple combinations for passwords. 

Sometimes, dictionary attacks employ patterns derived from previous data breaches, capitalizing on the tendency of users to reuse passwords across different services. Dictionary attacks are less resource intensive than brute force attacks and often more successful, especially against people who have weak password habits.

2. Impact on system resources

Brute force: High resource consumption

The brute force method is notably resource intensive. It requires significant computational power and time, especially as password complexity increases. Each additional character in a password exponentially increases the number of possible combinations, demanding more processing power and extending the time required for a successful breach. 

This high demand for resources often limits the feasibility of brute force attacks, especially against systems with robust security measures. However, with advancements in computing power — particularly through distributed computing and the use of bots — attackers can mobilize considerable resources, making even seemingly secure passwords vulnerable over time.

Dictionary: Lower resource consumption

Since dictionary attacks rely on a predefined list of likely passwords, the number of attempts needed is drastically lower than with brute force attacks. This efficiency not only makes dictionary attacks faster, but also less detectable, as they generate fewer abnormal access patterns that could trigger security protocols. 

The reduced resource requirement also means that dictionary attacks can be executed on less powerful systems, making them more accessible to a broader range of attackers. However, their success largely depends on the quality and relevance of the wordlist used, which may need regular updates to remain effective against current password trends.

3. Target vulnerabilities

Brute force: Targets weak passwords

Brute force attacks are particularly effective against systems without robust password requirements. These attacks thrive in environments where passwords are short, lack complexity, or aren’t updated regularly. 

Simple passwords — such as those using common words or basic sequences (like “12345” or “password”) — can be cracked in a matter of seconds with modern computing power. 

Systems that don’t implement adequate account lockout policies after multiple failed attempts also provide a fertile ground for brute force attacks. These environments allow attackers to make numerous attempts without being detected or blocked, significantly increasing the likelihood of a successful breach.

Dictionary: Targets human tendencies in password creation

Dictionary attacks exploit a different vulnerability: human behavior. Many people opt for passwords that are easy to remember. These choices often align with the contents of wordlists used in dictionary attacks, making them particularly susceptible. 

Additionally, dictionary attacks are effective against users who base their passwords on easily accessible personal information, such as birthdates, names, and favorite hobbies. Systems that don’t encourage or enforce unique, complex passwords are at a higher risk of being compromised by dictionary attacks. This vulnerability underscores the importance of educating users about secure password practices to reduce the risk of such attacks.

4. Speed and efficiency

Brute force: Slower due to the number of attempts required 

Brute force attacks have a fairly slow pace, primarily due to the sheer number of attempts required to find the correct password. The speed of a brute force attack is directly proportional to the complexity and length of the password. 

Longer and more complex passwords dramatically increase the number of possible combinations. As a result, cracking a password through brute force can be a time-consuming process, dependent in large part on the password’s complexity and the computational power available to the attacker.

Dictionary: Faster, since they leverage common passwords

In contrast, dictionary attacks are generally faster and more efficient. By leveraging lists of common passwords and phrases, these attacks can often bypass the need for countless combinations, targeting the most likely passwords first. 

The efficiency of dictionary attacks is enhanced when users employ simple, predictable passwords. The reliance on human predictability and common password trends allows these attacks to swiftly test a large number of likely passwords, making them particularly effective against systems with weaker password requirements. This efficiency underscores the need for awareness and education around secure password creation.

5. Effectiveness

Brute force: Lower success rate, but can crack any password

The effectiveness of brute force attacks is a double-edged sword. On one hand, these attacks have a lower success rate in the short term, primarily because of the enormous range of possible combinations they must attempt. This challenge is compounded when facing passwords of higher complexity and length. 

On the other hand, given enough time and computational resources, brute force attacks can eventually crack any password. This inevitability is a critical concern, especially as computing power continues to grow, reducing the time required for successful attacks.

Dictionary: Higher success rate but limited in scope

Dictionary attacks, by contrast, typically have a higher success rate, particularly against weak or common passwords. Since these attacks exploit the human propensity to use memorable and simple passwords, they’re often successful in breaching accounts where password security is not taken seriously. 

The effectiveness of dictionary attacks is significantly reduced against people who employ strong, unique passwords. This emphasizes the need for robust password policies and user education to mitigate the risks.

6. Predictability and detection

Brute force: More detectable 

Brute force attacks, given their methodical and exhaustive approach, tend to be more detectable by security systems. The high volume of login attempts over a short period is an unusual activity that can trigger alerts in many security protocols. 

Modern intrusion detection systems are designed to recognize these patterns and can often prevent a brute force attack from succeeding by locking out the user or IP address after a certain number of failed attempts. This visibility, however, also depends on the sophistication of the security system in place, as less advanced systems may not detect the attack until it’s too late.

Dictionary: More subtle 

Dictionary attacks, in contrast, are often more subtle and harder to detect. Since they use a list of common passwords and phrases, the number of attempts is significantly lower than with brute force attacks, making their access patterns resemble those of legitimate users. 

This subtlety allows dictionary attacks to fly under the radar of many conventional detection systems, especially if the attacker spaces out their attempts or uses different IP addresses. This stealthiness makes it crucial for security systems to not only look for the volume of access attempts, but also analyze login patterns and flag any anomalies that could suggest a dictionary attack.

7. Countermeasures and security implications

Brute force: Countered with strong security measures

To counteract brute force attacks, several measures can be implemented. One effective strategy is setting up lockout policies where an account is temporarily disabled after a certain number of failed login attempts. 

This approach hinders the attacker’s ability to try multiple password combinations in a short time period. Enforcing strong password policies is also helpful. Effective policies should require passwords to be frequently changed and of a certain length and complexity (a mix of letters, numbers, and special characters).

Dictionary: Countered through user education and policies

Mitigating dictionary attacks involves a combination of technical measures and user education. Educating people about the importance of strong, unique passwords is fundamental. Encouraging the use of phrases or combinations of words that are not easily guessable, along with a mix of characters, can reduce the vulnerability to dictionary attacks. 

Advanced policies, such as blocklisting commonly used passwords and implementing regular mandatory changes, also play a key role. These policies make it harder for attackers to use precompiled lists of common passwords effectively, thereby increasing the security of the system.

Similarities between brute force and dictionary attacks

The ultimate goal

Despite their differences, both brute force and dictionary attacks share the common goal of password compromise. They’re employed by attackers with the intent to gain unauthorized access to user accounts, systems, or data. In both cases, the attackers rely on the vulnerability of passwords as a security mechanism, exploiting the fact that they can be guessed, cracked, or otherwise overcome.

Countermeasures

Both types of attacks require continuous vigilance and adaptation in security practices. As attackers evolve their methods and tools, defenses against brute force and dictionary attacks also need to be updated and reinforced regularly. 

Strong password policies, regular password changes, and user education are effective against both types of attacks. Additionally, security measures, such as multifactor authentication, account lockout mechanisms, and monitoring for suspicious login attempts, provide a strong defense against both brute force and dictionary attacks. This overlap in countermeasures highlights the importance of a comprehensive security strategy that addresses multiple types of threats.

Countermeasures against brute force and dictionary attacks

1. A web application firewall (WAF)

A critical line of defense against both brute force and dictionary attacks is the use of a web application firewall (WAF). A WAF serves as the gatekeeper for incoming traffic to a website, filtering out suspicious activities and blocking malicious attempts. 

Implementing a WAF can help detect and prevent these attacks by setting rules that identify and block repeated login attempts or patterns typical of these attacks. For WordPress sites, Jetpack Security offers an efficient WAF that provides robust protection against such threats, preventing illegitimate traffic from reaching your site.

2. Strong password policies

Enforcing strong password policies is a fundamental countermeasure. This includes requiring passwords to be of a certain length and complexity, encouraging the use of alphanumeric and special characters, and discouraging the use of easily guessable information. Regularly updating these policies to keep up with evolving security threats is also vital.

3. Account lockout mechanisms

Implementing account lockout mechanisms after a set number of failed login attempts is a straightforward way to hinder brute force and dictionary attacks. This method prevents continuous password guessing by temporarily or permanently locking out the user or IP address after detecting suspicious activity.

4. Multifactor authentication (MFA)

Multifactor authentication adds a layer of security beyond just a password. By requiring additional verification, such as a code sent to a mobile device or biometric recognition, MFA significantly reduces the risk of unauthorized access, even if a password is compromised.

5. Limited login attempts

Restricting the number of login attempts within a certain time frame can effectively slow down and deter brute force and dictionary attacks. This approach limits the attacker’s ability to rapidly try different password combinations.

6. Intrusion detection and monitoring

Having robust intrusion detection and monitoring systems in place can help identify and respond to brute force and dictionary attacks in real time. These systems analyze patterns of login attempts and flag any unusual or suspicious activities.

7. Educate employees and users

Finally, educating employees and users about the importance of strong password practices and the threats posed by brute force and dictionary attacks is crucial. Awareness can lead to better password habits, which is a critical line of defense in cybersecurity.

Frequently asked questions

Can strong passwords prevent both brute force and dictionary attacks?

While strong passwords are significantly more resistant to both brute force and dictionary attacks, they’re not an infallible solution. They can drastically increase the difficulty of a successful attack, particularly against brute force attempts, where the number of possible combinations becomes vast. However, even the strongest passwords can be vulnerable through a brute force attack if other countermeasures are not active.

Additional security measures, such as a web application firewall (WAF) like the one included in Jetpack Security, are essential for comprehensive protection against these attacks.

What are the most common password patterns that dictionary attacks target?

Dictionary attacks typically target common password patterns such as sequential numbers (e.g., “123456”), common names, easily guessable words (like “password” or “qwerty”), and simple keyboard patterns (e.g., “asdfghjkl”). 

They also frequently include common substitutions, like using a zero instead of the letter ‘o,’ or dates of personal significance, such as birthdays.

Can password length alone protect against brute force attacks?

While password length is a critical factor in enhancing security, length alone is not sufficient. Combining length with complexity — including a mix of uppercase and lowercase letters, numbers, and special characters — is necessary to fortify passwords against brute force attacks. 

How should a business respond after detecting a brute force or dictionary attack?

Upon detecting a brute force or dictionary attack, a business should immediately strengthen its security protocols. This includes forcing password resets, reviewing and enhancing password policies, and examining security systems for any breaches. Additionally, it’s crucial to investigate the source of the attack and assess any potential data compromised during the incident.

Can WordPress websites be victims of brute force or dictionary attacks?

Yes, like any type of site, WordPress websites can be targets for both brute force and dictionary attacks. Employing strong WordPress security plugins, however, can dramatically reduce the likelihood of success. 

What can a WordPress website manager do to prevent brute force or dictionary attacks?

A WordPress website manager can implement several strategies to prevent brute force and dictionary attacks. These include enforcing strong password policies, limiting login attempts, using multifactor authentication, and implementing a web application firewall (WAF). 

Services like Jetpack Security can provide comprehensive dictionary and brute force attack protection, including many of the strategies discussed here.

Jetpack Security: Password attack protection for WordPress sites

Jetpack Security is a comprehensive solution for WordPress site protection, addressing the challenges posed by brute force and dictionary attacks, and so much more. This all-in-one security suite offers a range of features designed to strengthen WordPress sites against an array of threats.

With Jetpack Security, users gain access to real-time backups, ensuring that website data is always secure and recoverable in case of an attack. The integrated web application firewall (WAF) plays a critical role in monitoring and blocking suspicious login attempts, effectively countering potential brute force and dictionary attacks.

Jetpack Security’s malware scanning capability scans your site for vulnerabilities and malicious code, providing an added layer of protection. The 30-day activity log offers valuable insights into website interactions, enabling site managers to promptly identify and respond to any unusual activities. And the spam protection feature safeguards your site from spam submissions on your contact forms, registration forms, and comment sections.

Learn more about Jetpack Security for WordPress.