Brute Force Attack – Types, Examples & Preventing it

Introduction – Brute Force Attack in Cracking Hashes

In the beginning, there was darkness – and then, there was encryption. The concept of encryption has been around since the days of Julius Caesar, but it’s come a long way from simple substitution ciphers. Today, we’re going to focus on a particular aspect of encryption – hash functions, and the brute force attacks that are often used in an attempt to crack them.

Brute Force Attacks: An Overview

Brute force attacks. You’ve probably heard of them, but what are they? At their most basic, brute force attacks are trial-and-error methods used by attackers to gain unauthorized access to systems by guessing passwords, PINs, or encryption keys. Sounds scary, right? Well, it is, but there’s more to the story.

Understanding Hashes

Before we dive into the mechanics of brute force attacks, it’s important to understand what hashes are. Hashing is a method of encryption that takes an input (or ‘message’) and returns a fixed-size string of bytes. The output, called the ‘hash,’ is unique to each unique input. Even a tiny change to the input will produce such a drastic change in the output that the new hash will appear uncorrelated with the old hash.

Hashes are used all over the place, from password storage to data integrity checks, and they’re an essential part of the IT world.

Brute Force Attacks on Hashes

So how do brute force attacks fit into all of this? In the context of cracking hashes, a brute force attack involves attempting every possible combination of inputs until the attacker finds the one that produces the desired hash. It’s like trying every key on a key ring until you find the one that opens the door.

How Brute Force Attacks Work

Imagine you’ve got a lock and a bunch of keys. A brute force attack is essentially trying every key, one by one, until you find the one that opens the lock. In the context of hash cracking, the ‘lock’ is the hash you’re trying to crack, and the ‘keys’ are the potential inputs.

In theory, a brute force attack will always be successful eventually – after all, if you try every possible key, you’re bound to find the right one at some point. However, ‘eventually’ could be a very, very long time.

With the rise of powerful computers and the spread of botnets, attackers can now make a whopping 350 billion guesses per second. Yep, you read that right. They use tools and software specifically designed for this very purpose. A few examples? John the Ripper and Cain & Abel are some of the notorious ones. They’re like the Swiss Army knives for hackers.

The Process of Cracking Hashes

Cracking hashes involves a few steps. First, the attacker must obtain the hash they want to crack. This can be done in several ways, such as through a data breach or by intercepting network traffic.

Steps Involved in Brute Force Attacks

1. Obtain the hash: This is the starting point for any brute force attack on a hash.
2. Identify the hash algorithm: Hashes can be created using different algorithms, and the attacker must identify which one was used.
3. Set up the attack: The attacker configures their system to start trying different inputs.
4. Run the attack: The system tries different inputs, hashing each one and comparing the result to the target hash.
5. Find a match: Eventually, the system might find an input that produces the same hash. If it does, the attacker has successfully cracked the hash!

Types of Brute Force Attacks

Hold onto your hats, because it’s not just a one-size-fits-all approach. Oh no, there’s a little more spice in the mix.

1. Simple Brute Force Attack: This is the classic approach. The attacker tries every possible combination of characters until the correct password is found.
2. Dictionary Attack: Not as bookish as it sounds. Here, attackers use a pre-arranged list of words found in the dictionary. So if your password is “apple”, you’re in a bit of a pickle.
3. Hybrid Brute Force Attack: A fusion of sorts. Attackers mix dictionary words with numbers or symbols, gunning for those “apple123” or “banana$!” type passwords.
4. Rainbow Table Attack: Now, this one’s a tad complicated. Attackers use precomputed tables to find out password hashes. If that went over your head, think of it as the bad guys having a cheat sheet.

Brute Force Attack Examples

It’s not all fun and games. Once an attacker gains access, they can wreak havoc. Steal personal information, manipulate data, or even lock you out. And trust me, that’s just the tip of the iceberg.

Some High-Profile Victims

To show you that even the big fish aren’t safe:

• WordPress: In 2013, a massive botnet launched a large-scale Brute Force Attack on WordPress sites. Ouch!
• iCloud: Remember the 2014 celebrity photo leak? Yep, that was due to a Brute Force Attack.
• Telegram: In 2016, Iranian hackers supposedly brute-forced their way into Telegram messenger accounts. Talk about snooping!

Benefits of Brute Force Attacks

Admittedly, the word “benefits” sounds a tad counterintuitive when talking about a hacking technique. But from an attacker’s perspective (or sometimes ethical hackers testing system strengths), here’s what they’re looking at:

1. Simplicity: No need for sophisticated tactics; it’s as straightforward as it gets.
2. Universal Application: They can be used against almost any type of encryption or password system.
3. Effectiveness: Given enough time and computational power, they will almost always succeed.
4. No Insider Knowledge Needed: Unlike other tactics, no specific knowledge about the target system is required.
5. Automated Tools Available: Tools like John the Ripper make the job easier for hackers.
6. Great for Weak Passwords: Targets with weak or default passwords fall prey quickly.
7. Useful for Penetration Testing: Ethical hackers can use brute force to test system vulnerabilities.

Disadvantages of Brute Force Attacks

From a technical standpoint, and especially from a defensive angle:

1. Time-Consuming: Can take years to crack strong passwords.
2. Easily Detectable: Continuous login attempts can trigger alarms in most modern systems.
3. Resource-Intensive: Requires significant computational power for complex passwords.
4. Lockouts: Too many wrong attempts can lock out the account.
5. CAPTCHAs: Many websites now use CAPTCHAs that hinder automated login attempts.
6. Increased Awareness: Users are more educated now about creating complex passwords.
7. 2FA: Two-Factor Authentication adds an extra layer of defense.
8. Unpredictable Success Rate: Not always guaranteed to work, especially against robust defenses.

Applications of Brute Force Attacks

Where might you see these attacks in action?

1. Cracking Passwords: The most common application, be it for email accounts, databases, or social media.
2. Cryptanalysis: Decrypting encrypted data by trying every possible key.
3. Software Cracking: Bypassing software licenses or trial periods.
4. Penetration Testing: Ethical hackers test the robustness of a system using brute force.
5. Security Research: Finding vulnerabilities in encryption algorithms.
6. Digital Forensics: Sometimes used to access encrypted evidence.
7. Credential Stuffing: Using breached username/password pairs to access other accounts.
8. Testing CAPTCHA Effectiveness: Ensuring website CAPTCHAs are robust enough.
9. Game Cheat Development: Forcing through game protections to develop cheats.

Prevention of Brute Force Attacks

How can you shield yourself?

1. Complex Passwords: Always choose passwords with a mix of characters, numbers, and symbols.
2. Two-Factor Authentication (2FA): Add an extra layer of security.
3. Account Lockouts: After a certain number of wrong attempts, lock the account temporarily.
4. CAPTCHAs: Use them to prevent automated login attempts.
5. Rate Limiting: Limit the number of login attempts per unit time.
6. Monitor Login Attempts: Track multiple failed attempts and flag them.
7. Regularly Change Passwords: Make it a habit to update your passwords periodically.
8. Blacklist Known Attack IPs: Block IPs that are known to be malicious.
9. Use Security Plugins: Especially for platforms like WordPress, plugins can help fend off brute force attacks.
10. Educate & Train Employees: In an organizational setting, ensure that everyone understands the importance of security and knows how to create strong passwords.

Conclusion: Brute Force Attack

I’ve walked you through the ins and outs of brute force attacks in cracking hashes. We’ve looked at what they are, how they work, and the pros and cons of using them. They are a powerful tool in the arsenal of both attackers and defenders, a testament to the age-old adage, “knowledge is power.”

Brute force attacks in cracking hashes, while often viewed as the ‘bad guy’ in the world of cybersecurity, are also a valuable tool for security professionals. They remind us that no system is impervious, pushing us to design stronger, more secure systems.

So, is a brute force attack in cracking hashes a necessary evil? Perhaps. But it’s also a reminder of the importance of strong, unique passwords, secure systems, and vigilance in the face of potential attacks.

FAQs

1. What is a brute force attack?
A brute force attack is a trial-and-error method used to obtain information such as a user password or personal identification number (PIN).

2. How does a brute force attack work in cracking hashes?
In the context of cracking hashes, a brute force attack involves trying every possible combination of inputs until the attacker finds the one that produces the desired hash.

3. How can I protect myself against brute force attacks?
The best way to protect yourself against brute force attacks is to use strong, unique passwords. The longer and more complex your password, the harder it will be for an attacker to guess it.

4. Are brute force attacks always successful?
In theory, a brute force attack will always be successful eventually, given enough time and resources. However, ‘eventually’ could be a very long time, and many systems have measures in place to detect and block brute force attacks.

5. Can brute force attacks be used ethically?
Yes, brute force attacks can be used ethically by security professionals to test the strength of a system’s security and identify vulnerabilities.

6. What is a hash in the context of brute force attacks?
A hash is the output of a hash function, which is a method of encryption that takes an input and returns a fixed-size string of bytes. In the context of brute force attacks, the hash is the ‘lock’ that the attacker is trying to ‘open’ by guessing the correct input.