What is John the Ripper tool?
One of the oldest password cracking and testing tools, John the Ripper is still an essential pen testing tool.Phive2015 / Getty Images Show
John the Ripper definitionFirst released in 1996, John the Ripper (JtR) is a password cracking tool originally produced for UNIX-based systems. It was designed to test password strength, brute-force encrypted (hashed) passwords, and crack passwords via dictionary attacks. The tool comes in both GNU-licensed and proprietary (Pro) versions. An enhanced “jumbo” community release has also been made available on the open-source GitHub repo. The Pro version, designed for use by professional pen testers, has additional features such as bigger, multilingual wordlists, performance optimizations and 64-bit architecture support. Some of the key features of the tool include offering multiple modes to speed up password cracking, automatically detecting the hashing algorithm used by the encrypted passwords, and the ease of running and configuring the tool making it a password cracking tool of choice for novices and professionals alike. How does John the Ripper work?Password crackers and cryptanalysis tools typically work in three different ways. The common objective in all these is ultimately to correctly guess (“crack”) a password:
John the Ripper modesJtR provides at least three modes along with an “external” mode, which is basically letting a user define a customized mode via a configuration file.
John the Ripper usage examplesA detailed example use-case on John the Ripper’s website focuses on cracking a UNIX “shadow” file, which contains hashed passwords for user and system accounts. In newer UNIX-based distros, a list of users (usernames) along with other information is stored in the /etc/passwd file, whereas the password hashes corresponding to each user account are stored in a separate /etc/shadow file(s). Because passwd/shadow files are regarded highly confidential for obvious reasons (and stored with restrictive file permissions,
Running This will first run the “single crack” mode on your newly created mypasswd file, followed by the more extensive wordlist mode with default settings and lists, and if all that fails, JtR will resort to the powerful yet slow incremental mode. Should you wish to terminate a session by killing the application (e.g., via the Ctrl+C interrupt signal) and resume it later, you can do so by running: A complete list of usage examples is
available, whereas the manual pages for the application can easily be accessed by running: In a real-world scenario, before running any of the examples on practical data sets, it would be a good idea to set some of the options in the configuration files. For example, these options could be used to specify the text file you’d want JtR to use during the wordlist mode, or the range of password lengths (minimum and maximum) along with character sets the tool should be using when running under incremental mode. Overall, JtR is one of the oldest yet most familiar tools that professional pen testers still use when cracking passwords or checking password strengths. Its wide popularity, choice of free and open-source versions, as well as community support make it easily adoptable as a part of a hacker’s toolkit. Ax Sharma is an experienced cybersecurity professional and technologist who loves to hack, ethically and write about technology to educate a wide range of audiences. Copyright © 2020 IDG Communications, Inc. What is John the Ripper coded in?John the Ripper is part of Owl, Debian GNU/Linux, Fedora Linux, Gentoo Linux, Mandriva Linux, SUSE Linux, and a number of other Linux distributions. It is in the ports/packages collections of FreeBSD, NetBSD, and OpenBSD.
Do hackers use John the Ripper?One of the tools hackers use to crack recovered password hash files from compromised systems is John the Ripper (John). John is a free tool from Openwall.
Why is it called John the Ripper?The name "John the ripper" was coined by Lost Soul, a cracker from UNITED_cRACKING_fORCE, who coined this name after Jack the cracker (The password cracker that preceded John the ripper) -NOTE: The program was called "Cracker Jack", not Jack the cracker.
What is John the Ripper Kali?John the Ripper is a tool designed to help systems administrators to find weak (easy to guess or crack through brute force) passwords, and even automatically mail users warning them about it, if it is desired.
|