The Cisco switch must be configured to have all inactive Layer 3 interfaces disabled.
An inactive interface is rarely monitored or controlled and may expose a network to an undetected attack on that interface. Unauthorized personnel with access to the communication facility could gain access to a switch by connecting to a configured interface that is not in use. If an interface is no longer used, the configuration must be deleted and the interface disabled. For sub-interfaces, delete sub-interfaces that are on inactive interfaces and delete sub-interfaces that are inactive. If the sub-interface is no longer necessary for authorized communications, it must be deleted.
Disable all inactive interfaces as shown below: SW1(config)#interface GigabitEthernet3 SW1(config-if)#shutdown SW1(config)#interface GigabitEthernet4 SW1(config-if)#shutdown
Review the switch configuration and verify that inactive interfaces have been disabled as shown below: interface GigabitEthernet3 no switchport shutdown ! interface GigabitEthernet4 no switchport shutdown If an interface is not being used but is configured or enabled, this is a finding.