John the Ripper
OCAK 06, 2024 John the Ripper is a free password cracking software tool developed by Openwall that is widely used in penetration testing[2]. It is one of the most popular password cracking programs as it combines a number of password crackers into one package, autodetects password hash types, and includes a customizable cracker[2]. Here are some examples of how John the Ripper can be used:
- **Obtaining a copy of your password file**: If your system uses shadow passwords, you may use John's [command] to obtain a copy of your password file[1].
- **Using the incremental mode**: The most powerful cracking mode in John is called "incremental". You can use the default "incremental" mode parameters by running [command] [1].
- **Abbreviating options**: You can abbreviate options like "--single" as "-si" and "--format" as "-form"[2].
- **Viewing all formats**: To view all the formats that John the Ripper supports, run [command] [2].
- **Cracking passwords**: John the Ripper can be used to crack passwords, regardless of encrypted or hashed passwords, message authentication codes (MACs), and hash-based MACs (HMACs) [5]. It includes its own wordlists of common passwords for 20+ languages, which provide JtR with thousands of possible passwords from which it can generate the corresponding hash values to make a high-value guess of the target password[3].
- **Cracking SSH keys**: John the Ripper can be used to crack SSH keys. To do this, you need to convert the SSH key to a JtR compatible attack file using a conversion tool, and then point John the Ripper to the file with your dictionary[6].
- **Cracking Keepass2 databases**: Keepass2 is an open source, cross-platform, password management vault. John the Ripper can be used to crack Keepass2 databases by installing Keepass CLI ("kpcli") and then pointing John the Ripper to the database file with your dictionary[6].
It is important to note that John the Ripper can be used lawfully and unlawfully, and it is up to the user to ensure their usage is lawful[5].
Citations:
[1] https://www.openwall.com/john/doc/EXAMPLES.shtml
[2] https://www.hackingarticles.in/beginner-guide-john-the-ripper-part-1/
[3] https://www.varonis.com/blog/john-the-ripper
[4] https://www.csoonline.com/article/569533/john-the-ripper-explained-an-essential-password-cracker-for-your-hacker-toolkit.html
[5] https://www.techtarget.com/searchsecurity/tutorial/How-to-use-the-John-the-Ripper-password-cracker
[6] https://bytesoverbombs.io/cracking-everything-with-john-the-ripper-d434f0f6dc1c