The most common and easiest to understand example of the brute force attack is the dictionary attack to crack passwords. In this, the attacker uses a password dictionary that contains millions of words that can be used as a password. The attacker tries these passwords one by one for authentication. If this dictionary contains the correct password, the attacker will succeed.
To prevent password cracking from brute force attacks, one should always use long and complex passwords. This makes it hard for attackers to guess the password, and brute force attacks will take too much time. Account lockout is another way to prevent the attacker from performing brute force attacks on web applications. However, for offline software, things are not as easy to secure.
Similarly, for discovering hidden pages, the attacker tries to guess the name of the page, sends requests and sees the response. If the page does not exist, it will show a 404 response; on a success, the response will be 200. In this way, it can find hidden pages on any website.
Brute force is also used to crack the hash and guess a password from a given hash. In this, the hash is generated from random passwords and then this hash is matched with a target hash until the attacker finds the correct one. Therefore, the higher the type of encryption (64-bit, 128-bit or 256-bit encryption) used to encrypt the password, the longer it can take to break.
A reverse brute force attack is another term that is associated with password cracking. It takes a reverse approach in password cracking. In this, the attacker tries one password against multiple usernames. Imagine if you know a password but do not have any idea of the usernames. In this case, you can try the same password and guess the different usernames until you find the working combination.
Now, you know that a brute-forcing attack is mainly used for password cracking. You can use it in any software, any website or any protocol which does not block requests after a few invalid trials. In this post, I am going to add a few brute force password-cracking tools for different protocols.
I am sure you already know about the Aircrack-ng tool. This is a popular brute force wifi password cracking tool available for free. I also mentioned this tool in our older post on most popular password-cracking tools. This tool comes with WEP/WPA/WPA2-PSK cracker and analysis tools to perform attacks on Wi-Fi 802.11. Aircrack-ng can be used for any NIC which supports raw monitoring mode.
It basically performs dictionary attacks against a wireless network to guess the password. As you already know, the success of the attack depends on the dictionary of passwords. The better and more effective the password dictionary is, the more likely it is that it will crack the password.
It is available for Windows and Linux platforms. It has also been ported to run on iOS and Android platforms. You can try it on given platforms to see how this tool can be used for brute force wifi password cracking.
John the Ripper is another awesome tool that does not need any introduction. It has been a favorite choice for performing brute force attacks for a long time. This free password-cracking software was initially developed for Unix systems. Later, developers released it for various other platforms. Now, it supports fifteen different platforms including Unix, Windows, DOS, BeOS and OpenVMS.
This tool is very popular and combines various password-cracking features. It can automatically detect the type of hashing used in a password. Therefore, you can also run it against encrypted password storage.
Rainbow Crack is also a popular brute-forcing tool used for password cracking. It generates rainbow tables for using while performing the attack. In this way, it is different from other conventional brute-forcing tools. Rainbow tables are pre-computed. It helps in reducing the time in performing the attack.
L0phtCrack is known for its ability to crack Windows passwords. It uses dictionary attacks, brute force attacks, hybrid attacks and rainbow tables. The most notable features of L0phtcrack are scheduling, hash extraction from 64-bit Windows versions, multiprocessor algorithms and network monitoring and decoding. If you want to crack the password of a Windows system, you can try this tool.
In most cases, it can crack a Windows password in a few minutes. By default, Ophcrack comes with rainbow tables to crack passwords of less than 14 characters which contain only alphanumeric characters. Other rainbow tables are also available to download.
Hashcat claims to be the fastest CPU-based password cracking tool. It is free and comes for Linux, Windows and Mac OS platforms. Hashcat supports various hashing algorithms including LM Hashes, MD4, MD5, SHA-family, Unix Crypt formats, MySQL and Cisco PIX. It supports various attacks including brute force attacks, combinator attacks, dictionary attacks, fingerprint attacks, hybrid attacks, mask attacks, permutation attack, rule-based attacks, table-lookup attacks and toggle-case attacks.
Ncrack is also a popular password-cracking tool for cracking network authentications. It supports various protocols including RDP, SSH, HTTP(S), SMB, POP3(S), VNC, FTP and Telnet. It can perform different attacks including brute-forcing attacks. It supports various platforms including Linux, BSD, Windows and Mac OS X.
THC Hydra is known for its ability to crack passwords of network authentications by performing brute force attacks. It performs dictionary attacks against more than 30 protocols including Telnet, FTP, HTTP, HTTPS, SMB and more. It is available for various platforms including Linux, Windows/Cygwin, Solaris 11, FreeBSD 8.1, OpenBSD, OSX and QNX/Blackberry.
These are a few popular brute-forcing tools for password cracking. There are various other tools are also available which perform brute force on different kinds of authentication. If I just give an example of a few small tools, you will see most of the PDF-cracking and ZIP-cracking tools use the same brute force methods to perform attacks and crack passwords. There are many such tools available for free or paid.
Brute-forcing is the best password-cracking method. The success of the attack depends on various factors. However, factors that affect most are password length and combination of characters, letters and special characters. This is why when we talk about strong passwords, we usually suggest that users have long passwords with a combination of lower-case letters, capital letters, numbers and special characters. It does not make brute-forcing impossible but it does make it difficult. Therefore, it will take a longer time to reach to the password by brute-forcing.
Pavitra Shandkhdhar is an engineering graduate and a security researcher. His area of interest is web penetration testing. He likes to find vulnerabilities in websites and playing computer games in his free time. He is currently a researcher with InfoSec Institute.
Go beyond the iconic crack to learn how this State House bell was transformed into an extraordinary symbol. Abolitionists, women's suffrage advocates and Civil Rights leaders took inspiration from the inscription on this bell. Plan your visit to the Liberty Bell Center to allow time to view the exhibits, see the film, and gaze upon the famous cracked bell. No tickets are required and hours vary seasonally.
From Signal to Symbol The State House bell, now known as the Liberty Bell, rang in the tower of the Pennsylvania State House. Today, we call that building Independence Hall. Speaker of the Pennsylvania Assembly Isaac Norris first ordered a bell for the bell tower in 1751 from the Whitechapel Foundry in London. That bell cracked on the first test ring. Local metalworkers John Pass and John Stow melted down that bell and cast a new one right here in Philadelphia. It's this bell that would ring to call lawmakers to their meetings and the townspeople together to hear the reading of the news. Benjamin Franklin wrote to Catherine Ray in 1755, \"Adieu, the Bell rings, and I must go among the Grave ones and talk Politicks.\" It's not until the 1830s that the old State House bell would begin to take on significance as a symbol of liberty.
The Crack No one recorded when or why the Liberty Bell first cracked, but the most likely explanation is that a narrow split developed in the early 1840s after nearly 90 years of hard use. In 1846, when the city decided to repair the bell prior to George Washington's birthday holiday (February 23), metal workers widened the thin crack to prevent its farther spread and restore the tone of the bell using a technique called \"stop drilling\". The wide \"crack\" in the Liberty Bell is actually the repair job! Look carefully and you'll see over 40 drill bit marks in that wide \"crack\". But, the repair was not successful. The Public Ledger newspaper reported that the repair failed when another fissure developed. This second crack, running from the abbreviation for \"Philadelphia\" up through the word \"Liberty\", silenced the bell forever. No one living today has heard the bell ring freely with its clapper, but computer modeling provides some clues into the sound of the Liberty Bell.
Crack is produced by dissolving powdered cocaine in a mixture of water and ammonia or sodium bicarbonate (baking soda). The mixture is boiled until a solid substance forms. The solid is removed from the liquid, dried, and then broken into the chunks (rocks) that are sold as crack cocaine.
Individuals of all ages use crack cocaine--data reported in the National Household Survey on Drug Abuse indicate that an estimated 6,222,000 U.S. residents aged 12 and older used crack at least once in their lifetime. The survey also revealed that hundreds of thousands of teenagers and young adults use crack cocaine--150,000 individuals aged 12 to 17 and 1,003,000 individuals aged 18 to 25 used the drug at least once.
I have heard that hashing, such as MD5, is one-way and canno