The Cisco switch must not use the default VLAN for management traffic.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-101155	CISC-L2-000240	SV-110259r1_rule		Medium

Description
Switches use the default VLAN (i.e., VLAN 1) for in-band management and to communicate with directly connected switches using Spanning-Tree Protocol (STP), Dynamic Trunking Protocol (DTP), VLAN Trunking Protocol (VTP), and Port Aggregation Protocol (PAgP) - all untagged traffic. As a consequence, the default VLAN may unwisely span the entire network if not appropriately pruned. If its scope is large enough, the risk of compromise can increase significantly.

Description

Switches use the default VLAN (i.e., VLAN 1) for in-band management and to communicate with directly connected switches using Spanning-Tree Protocol (STP), Dynamic Trunking Protocol (DTP), VLAN Trunking Protocol (VTP), and Port Aggregation Protocol (PAgP) - all untagged traffic. As a consequence, the default VLAN may unwisely span the entire network if not appropriately pruned. If its scope is large enough, the risk of compromise can increase significantly.

STIG	Date
Cisco IOS Switch L2S Security Technical Implementation Guide	2020-05-07

Details

Check Text ( C-100035r2_chk )
Review the switch configuration and verify that the default VLAN is not used to access the switch for management: interface Vlan22 description Management VLAN ip address 10.1.22.3 255.255.255.0 If the default VLAN is being used for management access to the switch, this is a finding.

Fix Text (F-106859r1_fix)
Configure the switch for management access to use a VLAN other than the default VLAN: SW1(config)#int vlan 22 SW1(config-if)#ip add 10.1.22.3 255.255.255.0 SW1(config-if)#no shut