How does OSINT help with password cracking?

Open Source Intelligence (OSINT) is the craft of obtaining information from publicly accessible sources. While this may sound very straightforward, OSINT constitutes a vast body of tools for finding out information about a person, company, or other subject of interest. We can use this capability to reduce the time and complexity of password cracking in certain situations. How so? You may recall that we talked about the idea of password reuse in the last chapter.

In some scenarios, especially where we require users of a system to create passwords that are too complex to remember (or we require them to rotate these passwords too often), users may cheat the system by using the same password for many different systems. As an example, a user might choose a password that is complex but can be remembered, and set up that same password for several systems (for example, websites) and use this solution happily for some time.

Unfortunately, the...