Logical access (German: Zugang) is a BSI IT-Grundschutz term for the ability to log in to an IT system. It is used alongside physical access (Zutritt) and data access (Zugriff) as the three dimensions of access control. In an ISMS, controlling logical access is a core task: who may log in to which systems? Controls include user ID management, strong authentication, and regular access right reviews. ISO 27001 Annex A.5.15-A.5.18 cover identity and access management.