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Definition of Brute force attack

What is a brute force attack

A brute force attack is a hacking method when an attacker attempts to gain access to a system by sequentially testing all possible passwords or key combinations.

It is the same as picking the password to a locker but in the digital world. Despite its primitive nature, brute force attacks are quite spread and can be effective.

5 types of brute force attack

Despite its primitive nature, there are several types of brute force attacks, from the simplest to the most advanced.

Simple brute force attacks. The attackers use tools that allow them to quickly search through many possible character combinations, starting with the simplest ones. This may seem inefficient since most modern services encourage the combination of letters, registers, numbers, and symbols in a password. However, many people create passwords like 123456789Joe*.

Dictionary attacks. This brings us to the next type, namely dictionary attacks, in which the attacker uses a prepared dictionary of popular passwords to gain access. Ratings of such passwords are published yearly by independent research companies to encourage people to be more responsible. However, the top of the most popular passwords is still the sequential sets of numbers, with a couple of letters and symbols added. Besides the “popular” passwords it can also include common phrases, substitutions ("e" to "3"), and other predictable patterns.

Hybrid brute force attacks. This combines the previous methods, where the attacker simultaneously uses brute force and dictionaries of popular passwords. Or customizes the dictionary approach with user-specific information:  known user details like birthdates, pet names, etc., to increase the success rate. Most common combinations cannot withstand such an attack and give hackers access to data without much resistance if the system does not provide additional security methods.

Reverse brute force attacks. It is a type of brute-force attack in which an attacker uses a common password against multiple usernames in an attempt to gain access to a system.

Credential stuffing. This type of attack goes a little sideways and uses various data from previous hacks. Basically, it can use a list of credentials previously stolen in other attacks to hack into other accounts where users are utilizing the same passwords.

How to prevent brute force attacks

Using strong passwords. Encourage users to create complex passwords combining uppercase and lowercase letters, numbers, and symbols in a random and unique sequence.

Regular password updates. Recommend users keep passwords up to date and periodically change even strong passwords.

Multi-factor authentication (MFA). Utilizing two or more authentication methods greatly increases security by alerting the account owner of a login attempt and requiring additional confirmation.

Introducing CAPTCHA. Using graphical or audio verification tasks prevents automated hacking attempts, making them more time-consuming and, therefore, less profitable for the attacker.

Account lockout after multiple failed attempts. Limiting the number of password attempts within a certain period can also serve as a great defense method that gives additional time for the security team to detect and investigate suspicious activity.

Monitoring and analyzing security logs. Suspicious activity and timely response should be a constant practice where authorization attempts should definitely be checked.

Data encryption. The last line of defense is encryption, which makes hacking impractical for most attackers. In fact, even when data is accessed and encrypted, it remains useless to most hackers. Therefore, modern encryption methods are always necessary for data at rest and transmission.

Key Takeaways

  • A brute force attack is a fairly direct and simple hacking method that can be performed even by hackers who are not particularly experienced but have advanced automation tools.
  • Despite the primitive nature of this method, a huge number of systems are not resistant to it at all, as the use of simple passwords and the lack of additional security methods remains a very popular practice.
  • The combination of the method's simplicity and the multitude of unprotected systems makes it extremely favorable in the ratio of the time required to the probability of a successful hack.
  • Even basic strong password practices cannot always protect against this method, as several types of attacks do not directly brute force passwords but do so with other data.
  • A complete defense against brute force attacks involves several measures, including strong passwords, multi-factor authentication, strong security policies, and robust encryption.

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