Discuss how by using a known or previously unknown and newly discovered access mechanism, an attacker can gain access to a system or network resource through a back door. Point out that these doors are often referred to as maintenance hooks.

Stress that a back door, or trap door, access process is difficult to detect because the person or program that places it often makes the access exempt from the system’s usual audit logging features and makes every attempt to keep the back door hidden from the system’s legitimate owners.