A detailed footprint of an organisation’s Internet facing systems is a tactical resource that can be used by both red team (attackers) and the blue team (defenders).
penetration testers and blackhat hackers are using to map the attack surface. These tactics will often be also employed by targeted attackers. By quickly identifying weak areas in your attack surface you will enable prioritisation of mitigation to defend those systems and applications.
so that they can gain access and ensure that the engagement is successful. The nature of a penetration test is time constrained so the faster areas to attack are identified the more likely the test will be a success.