What is Password Cracking?
Password cracking is the process of guessing or recovering a password from stored locations or from data transmission system. It is used to get a password for unauthorized access or to recover a forgotten password. In penetration testing, it is used to check the security of an application.
In recent years, computer programmers have been trying to create algorithms for password cracking in less time. Most of the password cracking tools try to login with every possible combination of words. If login is successful, it means the password was found. If the password is strong enough with a combination of numbers, characters and special characters, this cracking method may take hours to weeks or months. A few password cracking tools use a dictionary that contains passwords. These tools are totally dependent on the dictionary, so success rate is lower.
In the past few years, programmers have developed many password cracking tools. Every tool has its own advantages and disadvantages. In this post, i will cover a few of the most popular password cracking tools.
Aircrack is a suite of tools for 802.11a/b/g WEP and WPA cracking. It implements the best known cracking algorithms to recover wireless keys once enough encrypted packets have been gathered. . The suite comprises over a dozen discrete tools, including airodump (an 802.11 packet capture program), aireplay (an 802.11 packet injection program), aircrack (static WEP and WPA-PSK cracking), and airdecap (decrypts WEP/WPA capture files). For downloads and more information, visit the Aircrack homepage.
Cain and Abel
UNIX users often smugly assert that the best free security tools support their platform first, and Windows ports are often an afterthought. They are usually right, but Cain & Abel is a glaring exception. This Windows-only password recovery tool handles an enormous variety of tasks. It can recover passwords by sniffing the network, cracking encrypted passwords using dictionary, brute-force and cryptanalysis attacks, recording VoIP conversations, decoding scrambled passwords, revealing password boxes, uncovering cached passwords and analyzing routing protocols. It is also well documented. For downloads and more information, visit the Cain and Abel homepage.
John the Ripper
John the Ripper is a fast password cracker for UNIX/Linux and Mac OS X.. Its primary purpose is to detect weak Unix passwords, though it supports hashes for many other platforms as well. There is an official free version, a community-enhanced version (with many contributed patches but not as much quality assurance), and an inexpensive pro version. You will probably want to start with some wordlists, which you can find here or here. visit the John the Ripper homepage.
When you need to brute force crack a remote authentication service, Hydra is often the tool of choice. It can perform rapid dictionary attacks against more then 30 protocols, including telnet, ftp, http, https, smb, several databases, and much more. Like THC Amap this release is from the fine folks at THC. Other online crackers are Medusa and Ncrack. The Nmap Security Scanner also contains many online brute force password cracking modules. visit the THC Hydra homepage.
Ophcrack is a free rainbow-table based cracker for Windows passwords (though the tool itself runs on Linux, Windows, and Mac). Features include LM and NTLM hash cracking, a GUI, the ability to load hashes from encrypted SAM recovered from a Windows partition, and a Live CD version. Some tables are provided as a free download but larger ones have to be bought from Objectif Sécurité. visit the ophcrack homepage.
Medusa is intended to be a speedy, massively parallel, modular, login brute-forcer. It supports many protocols: AFP, CVS, FTP, HTTP, IMAP, rlogin, SSH, Subversion, and VNC to name a few. visit the Medusa homepage.
fgdump is a newer version of the pwdump tool for extracting NTLM and LanMan password hashes from Windows. It is also capable of displaying password histories if they are available. It outputs the data in L0phtCrack-compatible form, and can write to an output file. fgdump attempts to disable antivirus software before running. It then runs pwdump, cachedump (cached credentials dump), and pstgdump (protected storage dump). visit the fgdump homepage.
L0phtCrack attempts to crack Windows passwords from hashes which it can obtain (given proper access) from stand-alone Windows workstations, networked servers, primary domain controllers, or Active Directory. In some cases it can sniff the hashes off the wire. It also has numerous methods of generating password guesses (dictionary, brute force, etc). LC5 was discontinued by Symantec in 2006, then re-acquired by the original L0pht guys and reborn as LC6 in 2009. visit the L0phtCrack homepage.
SolarWinds has created and sells dozens of special-purpose tools targeted at systems administrators. Security-related tools include many network discovery scanners, an SNMP brute-force cracker, router password decryption, a TCP connection reset program, one of the fastest and easiest router config download/upload applications available and more. visit the SolarWinds homepage.
The RainbowCrack tool is a hash cracker that makes use of a large-scale time-memory trade-off. A traditional brute force cracker tries all possible plaintexts one by one, which can be time consuming for complex passwords. RainbowCrack uses a time-memory trade-off to do all the cracking-time computation in advance and store the results in so-called "rainbow tables". It does take a long time to precompute the tables but RainbowCrack can be hundreds of times faster than a brute force cracker once the precomputation is finished. visit The RainbowCrack homepage.
Wfuzz is a tool for bruteforcing Web Applications, it can be used for finding resources not linked (directories, servlets, scripts, etc), bruteforcing GET and POST parameters for different kinds of injections (SQL, XSS, LDAP, etc.), bruteforcing form parameters (user/password), fuzzing, and more. visit Wfuzz homepage.
This Windows-only cracker bangs against network services of remote systems trying to guess passwords by using a dictionary and permutations thereof. It supports HTTP, POP3, FTP, SMB, TELNET, IMAP, NNTP, and more. No source code is available. UNIX users should take a look at THC Hydra. visit Brutus homepage.