Passive reconnaissance is something we do without directly interacting with our target, that is, we gather information about it from third parties such as search engines, cache databases, reputation monitoring sites, and many others.
In this recipe, we will be requesting information from multiple online services, also referred to as open source intelligence (OSINT), in order to build a general picture of our target and discover information that is useful from a penetration testing perspective, in the scenario that we are testing a publicly available site or application.