What is a Brute-Force Attack?

A brute-force attack involves an attacker attempting to guess a password or encryption key by trying every possible combination until the correct one is found. Brute-force attacks remain popular among cybercriminals due to their simplicity and effectiveness, even though it is one of the most straightforward and time-consuming attack methods.

These attacks pose a significant threat to the security of individuals, organizations, and governments worldwide. They're the most common threat vector used to target cloud email service providers, comprising 51% of all attacks in the first quarter of 2022, according to an analysis from Google Cloud. This article will discuss and explain different types of brute-force attacks, popular methods to carry them out, and the tools and techniques you can use to protect against them.

What Is a Brute-Force Attack?

Types of Brute Force Attacks Used to Guess Passwords Guardian Digital 1Download

Cybercriminals use brute-force attacks by systematically going through all possible combinations of characters to guess a password or encryption key, which will gain access to data or online accounts. Attackers use automated software to test thousands, or even millions, of potential passwords or key combinations until they find the correct one to enter the secure system. Such software is very effective in guessing weak or simple passwords, but this type of attack is also time-consuming and resource-intensive for the threat actors using them. Regardless, this method remains popular due to the valuable, sensitive data it often yields and has become increasingly helpful in the shift to remote and hybrid work environments. Hackers can benefit from brute-force attacks by stealing personal and activity data, profiting from ads, spreading malware to cause disruptions, hijacking systems for malicious activity, or damaging a website's reputation. There are multiple types of brute-force attacks, including:

  • Simple Brute-Force Attacks: Hackers attempt to logically guess simple passwords and login credentials without the assistance of software tools or other means. 
  • Dictionary Attacks: Hackers choose a target and run possible passwords with a known username. Dictionary attacks are the most basic brute force attack tool and are often used as a critical part of password cracking.
  • Hybrid Brute Force Attacks: Cybercriminals blend outside means with logical guesses to determine combinations of passwords that mix common words with random characters to attempt a break-in. A hybrid attack typically combines dictionary and simple attacks. 
  • Reverse Brute Force Attacks: Attackers start with a known password and search millions of usernames until they find a match. In many cases, cybercriminals start with leaked passwords that are available online from existing data breach.
  • Credential Stuffing: Threat actors recognize that users frequently reuse login information across many websites and exploit this poor security practice. If a malicious actor has a username-password combination that works for one website, they'll try it on many others. 


What Are Standard Tools Used in Brute-Force Attacks?

The most common tools leveraged in brute-force attacks are the ones that help automate the process of guessing credentials and finding combinations. These tools can find weak passwords, decrypt password data, run character combinations, and launch dictionary attacks. Some of the most popular brute-force attack tools include:

  • John the Ripper: John the Ripper is an open-source tool that enables users to deploy dictionary attacks and detect weak passwords through various cracking and decryption techniques.
  • Aircrack-ng: Aircrack-ng is an open-source penetration testing tool focused on wireless network security, permitting users to run dictionary attacks against network protocols.
  • Hashcat: Hashcat is a penetration testing platform that allows hackers to use known "hashes," or passwords run through a formula and converted into a string of random characters, which is always the same length, regardless of how much data the password contains. With this known data, they can use Hashcat to run dictionary or rainbow table attacks to reverse the password to readable text.

Are You At Risk?

If you utilize weak passwords (those that are short and easy to remember, without a combination of upper case, lower case, numeric, and special characters to add a layer of complexity), not only are you a part of the majority, but you face a heightened risk of suffering a brute-force attack. 83% of Americans create weak passwords in length (less than ten characters), and character complexity (only numbers and letters), and 53% use the same passwords across accounts. Many users' account credentials include personal information that can be easily accessed online, such as their name, birth date, or hobbies. These factors add simplicity and convenience for cybercriminals looking to use brute-force attacks to steal proprietary information or data to sell on the dark web, lock out administrators until they receive a ransom payment, or infect systems with malware for economic, political, or social reasons.

If you are targeted in a brute-force attack, there is an extremely high likelihood of success, and you will suffer the above consequences, as this type of threat tends to have a 100% success rate for attackers. However, adversaries may have to wait years for their automated systems to guess a complex password correctly.

Prevention & Mitigation Strategiesinternet security concept, user access login and password on computer, secured data online

Although brute-force attacks are overall very effective in guessing credentials, by engaging in the following best practices for email security and cybersecurity, you can significantly reduce the likelihood of falling victim to an attack:

T-Mobile IT Servers Breached with Brute-Force Attacks, Personal Information of 54 Million People Stoles

In 2021, malicious hackers used brute-force attacks to access T-Mobile IT servers, resulting in the 54 milliT-mobile news headlineon people facing data loss and theft, including social security numbers, names, phone numbers, and addresses, as well as device identifiers and PINs for specific accounts. Current, former, and prospective T-Mobile customers were among those with personal information stolen. This attack led to harsh criticism of T-Mobile's security, as even the hacker responsible for the breach, 21-year-old John Binns, said that T-Mobile's "security is awful," and he found an unprotected router after using a publicly available tool to search weak spots in T-Mobile's known Internet addresses. This access point allowed him to illegally hack into a data center, where he then gained access to over 100 servers via stored credentials and, about a week later, cracked into the T-Mobile customer data files.

Understanding how easy it is to hack into various email security systems is crucial in formulating distinct, difficult-to-hack passwords and protecting your personal and business networks.

Keep Learning About Brute-Force Attacks

Brute-force attacks are used to gain unauthorized access to a system by taking advantage of common credential vulnerabilities such as poorly designed, recycled, and stagnated passwords.

Hackers will use various brute-force methods, offline and online approaches, and sophisticated tools to obtain correct credential information quickly. By implementing the tips and best practices for email security shared in this article, you can significantly reduce your chances of suffering the damaging consequences of a brute-force attack.

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