How to use John the Ripper to crack passwords

The open source John the Ripper password cracker is a key tool for red and blue team members alike. Red teams use it to gain access to systems and blue teams use it to detect weak passwords and test defenses. In this video, Ed Moyle of Drake Software explains how to use John the Ripper to crack Linux and Windows passwords, as well as passwords encrypted with an SSH key. Editor's note: Password cracking tools can be used lawfully and unlawfully. It is up to you to ensure your usage is lawful. Get appropriate permission and approval prior to attempting to use any password cracker, and handle the information obtained ethically. If you are unsure whether your usage is lawful, do not proceed until you have confirmed that it is -- for example, by discussing and validating your planned usage with your organization's counsel.