A corporate footprint will determine how much data an attacker can enumerate for a targeted attack against your company. This would constitute part of the reconnaissance phase of an attack and could be used to map your network or corporate structure.
This assessment searches for public facing business data, employee data and external facing computer systems such as email servers or websites. This data is useful for spear-phishing, further exploitation and gaining internal network access.
A corporate footprint allows you to evaluate the risks associated with public facing information and will provides suitable recommendations on reducing possible attack vectors.