What is a brute force attack in cyber security?

A brute force cyber attack is a straightforward method used to gain unauthorised access to systems. Due to its simplicity, brute force attacks are quite common. Understanding how brute force attacks work, recognising their various types, and implementing effective defensive strategies are crucial for safeguarding your business's networks.

What is a brute force attack?

A brute force attack is a cyber-attack that uses trial and error to try and crack passwords. Using automated tools, hackers attempt to input thousands of common passwords, along with various keys and numbers, to identify the correct password combination. While it may seem straightforward- and it is- the approach’s simplicity does not diminish its effectiveness in any way.

How does a brute force attack work?

The efficacy of brute force attacks comes from the method's trial-and-error approach. While it may seem incredibly long-winded to trawl through thousands of phrases for a single password, automated tools speed up the process tenfold, making this task effortless for malicious hackers. Here's how it works:

• Hackers select an automated tool- or purchase a malware kit from the dark web- to trawl through thousands of password combinations swiftly.
• The automated tool continues to run through all of the possible password combinations until a correct password is identified. The simpler and shorter the password, the quicker it is to identify and exploit.
• From there, the malicious hacker now has access to whatever account they were seeking to exploit, victimising user accounts and leaving personal, financial, and sensitive data vulnerable.

Types of brute force attacks

Brute force attacks are frequently combined with other aggressive attack techniques to breach your networks. Below are the traditional brute force attack methods used by hackers:

Simple brute force attacks

A simple brute force attack relies on poor password security to guess passwords. It's the most common brute force attack method, and, using automated tools, will make hundreds to thousands of password guesses every second.

Dictionary attacks

Dictionary attacks use words from the dictionary and combine them in thousands of ways to try and identify a correct password combination. Dictionary software- used by malicious hackers- can also substitute certain letters with similar characters to generate alternative guesses. For example, dictionary software would test both "chicken" and perhaps also "ch1cken", and "chick3n".

These recent advancements in malicious software make it all the more easy for hackers to identify the correct password.

Hybrid attacks

Hybrid brute force attacks combine the methodology of dictionary attacks with simple brute force attacks. Hybrid brute force attacks involve using a list of common passwords and quickly trying different character swaps and combinations. This approach blends using known passwords with random character changes to crack passwords more effectively.

Reverse brute force attacks

Reverse brute force attacks target authentication systems by testing a small number of common passwords against many different usernames, flipping the traditional brute force approach that tries many passwords against a single account.

When is a brute force attack effective?

Brute force attacks are most effective when the target does not follow password creation best practices. When a website you are signing up for prompts you to include special characters and capital letters in your password, it is not to inconvenience you. In fact, it is to protect you from this pervasive attack method and minimise the risk of your account being exploited.

Short, simple, or predictable passwords significantly increase the efficacy of brute-force attacks. "Password123" is an example of this: sequential numbers and obvious phrases are not as impenetrable as you might think!

A lack of implemented account lockout methods also increases the likelihood of exploitation. System passwords should only be allowed to be inputted a few times incorrectly before a temporary lockout is issued, and the owner's account is alerted, typically via email or SMS.

These protective systems prevent hackers from being able to try passwords relentlessly.

What are the signs of a brute force attack?

Although brute force attacks strive for stealth, certain indicators can reveal that an attack is in progress. Here are a few key identifiers to help you detect brute-force attacks:

• Multiple failed login attempts: A sudden surge in failed login attempts can indicate a brute force attack or stolen credentials. Attackers use automated tools to try numerous password combinations, leading to an unusual number of failed access attempts. Monitoring login logs for such spikes can help detect these attacks early.
• Unusual activity on user accounts: If you notice unfamiliar actions on your account, such as changes in settings, unauthorised transactions, or messages sent without your knowledge, it could be a sign of a successful brute force attack. Regularly reviewing account activity can help identify these anomalies.
• Spikes in network traffic: A significant increase in network traffic, especially from unknown IP addresses, could be a brute force attack in progress. Attackers often use botnets to distribute their attack efforts, causing clear traffic spikes. Employing network monitoring tools can assist in detecting these unusual patterns.

How to protect against brute force attacks

Some key methods for protecting your organisation against brute force attacks include:

Using strong, complex passwords

To effectively defend against brute force attacks, one of the most fundamental steps is to use strong, complex passwords. Avoid creating weak passwords that are easy to guess by using a combination of uppercase and lowercase letters, numbers, and special characters. Each user account should have a unique password, and it is advisable to change passwords regularly to maintain security.

Implementing multi-factor authentication

Enhance your security by implementing multi-factor authentication (MFA). This additional layer of security requires users to verify their identity through multiple methods, such as a password and a one-time code sent to their mobile device. MFA significantly reduces the risk of unauthorised access, even if a password is compromised.

Using a password manager

A password manager can help generate and store complex passwords for each user account, ensuring that you do not have to remember them all. This tool also aids in avoiding the reuse of passwords across multiple accounts, which can be a vulnerability if one account is compromised.

Setting account lockout policies

Establish account lockout policies to prevent repeated login attempts. After a certain number of failed login attempts, temporarily lock the user account and alert the account owner. This makes it more difficult for attackers to use automated tools to compromise passwords.

Monitoring for unusual login attempts

Regularly monitor login attempts for unusual activity, such as a sudden increase in failed login attempts or access from unfamiliar locations. Implementing monitoring tools can help detect and respond to brute force attacks promptly, minimising potential damage.

What are the consequences of a successful brute force attack?

Successful brute force attacks can be incredibly detrimental to an organisation's functions. Since so many of us use the same password across several accounts and websites, a breached password on one network often guarantees access to several other platforms, providing hackers access to all sorts of sensitive information.

In a professional setting, brute force attacks can lead to data breaches, the exploitation of sensitive information, and unauthorised access to critical systems- all capable of having an exponentially negative impact on your daily operations, client trust, and business integrity.

How to respond to a brute force attack

In the instance a brute force attack is identified, here is how to best respond to minimise risk and swiftly remediate any damages:

Blocking the attacker’s IP address

Blocking the attacker's IP address is a crucial step in halting a brute force attack. By identifying the source of the attack and blocking the IP address at the network level, you can prevent further unauthorised access attempts. This step should be taken swiftly to minimise any potential damage. Additionally, maintaining an updated list of known malicious IP addresses can help proactively defend against future attacks.

Changing compromised passwords

Once a brute force attack is detected, it's vital to change any compromised passwords immediately. This action helps secure the affected user accounts and prevents further unauthorised access. Encourage users to create strong, complex passwords that incorporate uppercase and lowercase letters, numbers, and special characters.

Implementing a password expiration policy can also help ensure passwords are regularly updated, reducing the risk of exploitation.

Alerting the relevant team

Alerting the relevant team is essential for a coordinated response to a brute force attack. This team may include IT security professionals, system administrators, and any other stakeholders responsible for managing cybersecurity threats.

Prompt communication ensures that all necessary steps are taken to mitigate the attack, assess the extent of the breach, and restore system integrity. Additionally, informing users whose accounts may have been compromised allows them to take action to secure their data.

How can threat intelligence prevent a brute force attack?

Threat intelligence is one of your organisation's best defences against brute force attacks. Continuous threat intelligence scanners, like OnSecurity's Radar, can protect your business proactively against malicious attackers by flagging IOCs (Indicators of Compromise) as soon as they're identified.

Threat intelligence can also flag if employees are re-using passwords across multiple sites, minimising the risk of exploitation by promoting best practices before hackers can take advantage.

By demonstrating proactivity through threat intelligence software, promoting strong password policies at work, and setting up account lockout procedures, organisations can lower the risk of brute force attacks and protect their critical systems and data.

Empower your cybersecurity strategy and mitigate the risk of brute force attacks today, visit our scan page and see our radar page.