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 themselves inactive. If the sub-interface is no longer necessary for authorized communications, it must be deleted.

Review the switch configuration and verify that inactive interfaces have been disabled as shown below:

interface Ethernet4/12 shutdown no switchport

interface Ethernet4/13 shutdown no switchport … … … interface Ethernet4/48 shutdown no switchport

If an interface is not being used but is configured or enabled, this is a finding.

Disable all inactive interfaces as shown below:

SW1(config)# int e4/1 - 11 SW1(config-if-range)# shutdown SW1(config-if-range)# end