Banner grabbing or sometimes called footprinting is the process of gathering every information about a target network and organization using various methods. The aim is to find out the OS version deployed, default configurations, services running, patching and upgrading history, just to name a few. This activity is common during penetration testing procedures.
The process of gathering information may target publicly available as well as secret sources, as deemed necessary for the attack. Besides, it is the groundwork to launch further attacks in reconnaissance, exploitation and so on stages.
the_cyberguy Edited answer 14/07/2022