This document defines a process reference model (PRM) for the domain of information security management, which is meeting the criteria defined in ISO/IEC 33004 for process reference models (see Annex A). It is intended to guide users of ISO/IEC 27001 to: — incorporate the process approach as described by ISO/IEC 27000:2018, 4.3, within the ISMS; — be aligned to all the work done within other standards of the ISO/IEC 27000 family from the perspective of the operation of ISMS processes — support users in the operation of an ISMS ? this document is complementing the requirements-oriented perspective of ISO/IEC 27003 with an operational, process-oriented point of view.