In the event of an APT attack, the attacker obtains detailed knowledge of how the target environment is structured and configured. They will be familiar, for example, with the existing network segments, the naming schemes for IT systems and user and service accounts, and the software and services used. This knowledge may enable the same attacker to regain access to the target environment after the cleaning process is complete. They can move within the network in a targeted, efficient, and unobtrusive manner and quickly achieve a high degree of infection once more.