Check: CISC-L2-000220
Cisco NX OS Switch L2S STIG:
CISC-L2-000220
(in versions v2 r3 through v1 r0.1)
Title
The Cisco switch must not have the default VLAN assigned to any host-facing switch ports. (Cat II impact)
Discussion
In a VLAN-based network, switches use the default VLAN (i.e., VLAN 1) for in-band management and to communicate with other networking devices 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.
Check Content
Review the switch configurations and verify that no access switch ports have been assigned membership to the default VLAN (i.e., VLAN 1). VLAN assignments can be verified via the show vlan command. In the example below, interfaces 1/1 and 1/2 are trunk links. SW1# show vlan VLAN Name Status Ports ---- -------------------------------- --------- ------------------------------- 1 default active Eth1/1, Eth1/2 10 VLAN0010 active Eth1/1, Eth1/2, Eth1/3, Eth1/4 Eth1/5, Eth1/6, Eth1/7, Eth1/8 Eth1/9, Eth1/10, Eth1/11 Eth1/12, Eth1/13, Eth1/14 Eth1/15, Eth1/16, Eth1/17 Eth1/18, Eth1/19, Eth1/20 Eth1/21, Eth1/22, Eth1/23 Eth1/24, Eth1/25, Eth1/26 Eth1/27, Eth1/28, Eth1/29 Eth1/30 11 VLAN0011 active Eth1/1, Eth1/2, Eth1/31 Eth1/32, Eth1/33, Eth1/34 Eth1/35, Eth1/36, Eth1/37 Eth1/38, Eth1/39, Eth1/40 If there are access switch ports assigned to the default VLAN, this is a finding.
Fix Text
Remove the assignment of the default VLAN from all access switch ports.
Additional Identifiers
Rule ID: SV-220691r539671_rule
Vulnerability ID: V-220691
Group Title: SRG-NET-000512-L2S-000008
Expert Comments
CCIs
Number | Definition |
---|---|
CCI-000366 |
The organization implements the security configuration settings. |
Controls
Number | Title |
---|---|
CM-6 |
Configuration Settings |