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Brute Force Attacks: A Persistent Threat in the Digital Age

Brute force attacks remain one of the most prevalent forms of cyber attacks despite being one of the oldest. Its effectiveness stems from two key factors: a low barrier to entry and the continued use of weak passwords.

Unlike more sophisticated attacks that exploit vulnerabilities, brute force requires minimal technical expertise, making it accessible to a wide range of attackers.

Moreover, the tendency to use simple and easy-to-remember passwords significantly increases the success rate of brute-force attacks. Research shows that “123456” continues to be the most commonly used password worldwide, highlighting the need for stronger password practices.

What is a brute force attack, and how does it work?

A brute force attack is a systematic trial-and-error approach employed by attackers to guess login credentials, such as usernames and passwords. Attackers aim to gain unauthorized access to a system or account by systematically attempting every possible combination of characters.

A successful brute force attack can have devastating consequences. Hackers who gain unauthorized access can:

  • Hold the system hostage: This involves encrypting critical data and demanding a ransom for decryption.
  • Move laterally within the network: Once inside, attackers can exploit compromised credentials to access other systems within the network.
  • Create backdoors: Backdoors are malicious tools left behind by attackers to facilitate attacks in the future.
  • Leak or steal sensitive information: Hackers may steal personal data, customer information, or intellectual property for financial gain or competitive advantage.

Traditionally, brute force attacks were manual endeavors. Hackers might attempt to guess passwords based on readily available information about a target, such as their name, birthdate, or common phrases. They might also employ lists of commonly used words and phrases to increase their success rate.

However, the rise of automation has significantly amplified the threat. Bot-based attacks leverage malicious software programs, or bots, to automate the login attempt process. These bots can attempt thousands of password combinations in a fraction of a second, vastly increasing the attacker’s efficiency and the likelihood of a successful breach.

Furthermore, the dark web provides a marketplace for cybercriminals. Ready-to-use malware kits containing automated brute-force attack tools are readily available for purchase. Additionally, stolen credential lists compiled from previous data breaches can be obtained to further enhance the attacker’s success rate.

Here are other types of brute force attacks that threat actors leverage:

1.     Traditional method

This is the most basic form of a brute-force attack. Attackers systematically try every possible combination of characters until they stumble upon the correct one. This method proves inefficient for complex passwords, but it can be successful against short, simple passwords with limited character variations.

2.     Dictionary method

This method leverages pre-existing databases containing common passwords, usernames, and phrases. The attacker feeds this list into an automated program that attempts each entry on the target system. Dictionary attacks are faster than traditional methods, especially with variations like adding numbers or symbols to common words.

3.     Hybrid method

This approach combines the traditional and dictionary methods. The attack might begin by attempting entries from a dictionary and then move on to systematically testing different character combinations. Hybrid attacks are more targeted than traditional methods and can be particularly dangerous if the attacker has some knowledge about the victim’s potential password choices.

4.     Botnet brute-force

Botnets are networks of compromised devices controlled by a single attacker. In a botnet brute force attack, the attacker leverages the combined processing power of these infected devices to bombard a target system with login attempts at an exponentially faster rate. This significantly increases the success rate, especially against weak login defenses.

5.     Credential stuffing

This attack involves using stolen username and password combinations from data breaches on other platforms. Attackers attempt to use these stolen credentials on various websites, banking on the possibility that users reuse passwords across multiple accounts. Credential stuffing attacks are automated and can be highly successful if users don’t practice unique, strong passwords.

6.     Reverse brute force

Unlike the other methods, which focus on guessing passwords, a reverse brute force attack attempts to guess usernames associated with a known email address or password. This can be useful for attackers who have access to leaked password databases and want to identify the corresponding usernames for targeted attacks.

Measures to mitigate brute force attacks

Weak passwords are the root cause of brute force attacks. While the most straightforward solution seems to be enforcing strong, unique passwords across all accounts, user adoption presents a significant challenge. Creating and remembering complex passwords for multiple platforms can be cumbersome, leading users to resort to the less secure option of reusing simple passwords.

This is where passwordless authentication emerges as a promising solution. By relying on inherent user characteristics, such as fingerprints or facial recognition, passwordless authentication eliminates the need for passwords altogether. These unique biometric factors are virtually impossible for attackers to replicate, significantly strengthening security against brute force attacks.

Along with this, cyber hygiene measures are as critical as ever. Here are a few measures enterprises can take to prevent brute force attacks:

1.     Limit login attempts

Implement a system that automatically locks accounts after a predefined number of consecutive failed login attempts. This prevents attackers from relentlessly attempting various password combinations. The lockout duration can be configured to be temporary (a few minutes) or require manual intervention by an administrator.

  1. Employ CAPTCHA

A CAPTCHA can be presented when a login attempt is made, requiring the user to decipher a distorted image or solve a simple math problem. Bots typically struggle with these challenges, significantly reducing the effectiveness of automated brute force attacks.

3.     Install Intrusion Detection System (IDS)

An IDS is security software that monitors network traffic for malicious activity, including suspicious login attempts. It can detect brute-force attacks by identifying patterns of frequent failed logins from a single source IP address. The IDS can trigger alarms, lock accounts, or block suspicious IP addresses upon detection.

4.     Monitor Login Activity and Have an Incident Response Plan

Regularly monitor login activity for suspicious patterns, such as failed login attempts from unusual locations or occurring at odd times. This vigilance can help identify potential brute force attacks in their early stages. Additionally, having a well-defined incident response plan outlines the steps to take in case of a security breach, including user notification, account recovery procedures, and containment measures to prevent further damage.

Conclusion

Brute force attacks’ backbone is exploiting passwords, and by eliminating the use of easy-to-guess and repetitive passwords across accounts, enterprises can significantly reduce the attacks and attempts of brute force. Besides, maintaining cyber hygiene is always a great way to stop these attacks from happening in the future and safeguard your enterprise’s sensitive information.

 

(The author is  by Mr. Shibu Paul, Vice President – International Sales at Array Networks, and the views expressed in this article are his own)