This is called the ' birthday problem ' in mathematics. The same type of analysis can be applied to hash functions in order to find any two hashes which match instead of a specific hash which matches the other. To avoid this, you can use longer hash functions such as SHA3, where the possibility of collisions is lower. You can try to brute force hashes, but it takes a very long time. The faster way to do that, is to use pre-computed rainbow tables which are similar to dictionary attacks. The most important thing to remember about hacking is that no one wants to do more work than they have to do.
For example, brute forcing hashes can be extremely time consuming and difficult. If there's an easier way to get your password, that's probably what a nefarious actor will try first. That means that enabling basic cyber security best practices is probably the easiest way to prevent getting hacked.
In fact, Microsoft recently reported that just enabling 2FA will end up blocking Popular password cracking tools. If you read this far, tweet to the author to show them you care. Tweet a thanks. Learn to code for free. Get started. Forum Donate. Megan Kaczanowski. Let's start with the basics. What is a brute force attack?
How to protect yourself This type of attack can be defended against in a couple of different ways. How can you crack passwords faster? What if you already have a list of hashed passwords? Wait a minute - what's hashing? What's an example of how hashes are used? Hashes can be used as verification that a message hasn't been changed.
What's the problem with hashes? However, passwords can also introduce security vulnerabilities. Password crackers are designed to take credential data stolen in a data breach or other hack and extract passwords from it. This would make it far too easy for a hacker or a malicious insider to gain access to all of the user accounts on the system. Instead, authentication systems store a password hash, which is the result of sending the password — and a random value called a salt — through a hash function.
Hash functions are designed to be one-way, meaning that it is very difficult to determine the input that produces a given output. Since hash functions are also deterministic meaning that the same input produces the same output , comparing two password hashes the stored one and the hash of the password provided by a user is almost as good as comparing the real passwords.
Password cracking refers to the process of extracting passwords from the associated password hash. This can be accomplished in a few different ways:. Most password-cracking or password finder tools enable a hacker to perform any of these types of attacks.
This post describes some of the most commonly used password-cracking tools. Hashcat is one of the most popular and widely used password crackers in existence. It is available on every operating system and supports over different types of hashes. Hashcat enables highly-parallelized password cracking with the ability to crack multiple different passwords on multiple different devices at the same time and the ability to support a distributed hash-cracking system via overlays.
Cracking is optimized with integrated performance tuning and temperature monitoring. Download Hashcat here. A Windows version is also available. John the Ripper offers password cracking for a variety of different password types.
A pro version of the tool is also available, which offers better features and native packages for target operating systems. Download John the Ripper here. Brutus is one of the most popular remote online password-cracking tools. It claims to be the fastest and most flexible password cracking tool.
This tool is free and is only available for Windows systems. It was released back in October Brutus supports a number of different authentication types, including:.
It is also capable of supporting multi-stage authentication protocols and can attack up to sixty different targets in parallel. It also offers the ability to pause, resume and import an attack.
Brutus has not been updated for several years. However, its support for a wide variety of authentication protocols and ability to add custom modules make it a popular tool for online password cracking attacks. Get the Brutus password finder online here. Wfuzz is a web application password-cracking tool like Brutus that tries to crack passwords via a brute-force guessing attack.
It can also be used to find hidden resources like directories, servlets and scripts. THC Hydra is an online password-cracking tool that attempts to determine user credentials via brute-force password guessing attack.
THC Hydra is extensible with the ability to easily install new modules. Download THC Hydra here. Medusa is an online password-cracking tool similar to THC Hydra. It claims to be a speedy parallel, modular and login brute-forcing tool. Medusa is a command-line tool, so some level of command-line knowledge is necessary to use it.
Password-cracking speed depends on network connectivity. On a local system, it can test 2, passwords per minute. Medusa also supports parallelized attacks. In addition to a wordlist of passwords to try, it is also possible to define a list of usernames or email addresses to test during an attack.
Read more about this here. Download Medusa here. All password-cracking is subject to a time-memory tradeoff. This threat is why passwords are now salted: adding a unique, random value to every password before hashing it means that the number of rainbow tables required is much larger. RainbowCrack is a password cracking tool designed to work using rainbow tables.
It is possible to generate custom rainbow tables or take advantage of preexisting ones downloaded from the internet. Download rainbow tables here. Ophcrack is a cross-platform Windows password cracker that uses rainbow tables to crack passwords.
It also has a module for brute force attacks among other features. In this practical scenario, we are going to crack Windows account with a simple password. Windows uses NTLM hashes to encrypt passwords. We will use the dictionary attack in this example. You will need to download the dictionary attack wordlist here 10k-Most-Common. For this demonstration, we have created an account called Accounts with the password qwerty on Windows 7.
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