Devices in an FC-SAN are managed and assigned internally using world wide names (WWNs). They are similar in some ways to the MAC addresses of Ethernet network adapters. Using programs made available by the manufacturers of host bus adapters (HBA), the WWN of an HBA may be changed. An attacker may thus access data without corresponding authorisation. The manipulation of WWNs, also referred to as WWN spoofing, poses a considerable damage risk to an organisation. Particularly in connection with multi-client-capable storage systems, unauthorised persons may access the information of other clients.