Selecting and using John rules

Like hashcat, John has a tremendous amount of support for creating and using custom rules to interact with our candidates to increase the chances of a successful crack. The number of options will easily become overwhelming. In many cases, it may be better to start with a sample file with some common rules, alongside code comments that make it clear what a particular rule does.

Note

There are great resources on the internet for this topic. Refer to https://www.openwall.com/john/doc/RULES.shtml, as well as https://www.openwall.com/john/doc/EXAMPLES.shtml, for some additional guidance.

These documents can also be found locally under the /doc directory, where John was cloned, as we described in Chapter 3. See Figure 4.1 for a list of the current documentation in john 1.9.0-Jumbo-1:

Figure 4.1 – The list of documentation installed alongside John

Rules are set up and configured for repeated use in the john.conf...