The Dell OS10 Switch must not have the default VLAN assigned to any host-facing switch ports.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-269967	SRG-NET-000512-L2S-000008	OS10-L2S-000220	SV-269967r1052287_rule	2024-12-11	1

Description
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. Therefore, 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

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. Therefore, 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.

ℹ️ Check
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: OS10# show vlan Codes: * - Default VLAN, M - Management VLAN, R - Remote Port Mirroring VLANs, @ - Attached to Virtual Network, P - Primary, C - Community, I - Isolated, S - VLAN-Stack VLAN Q: A - Access (Untagged), T - Tagged NUM Status Description Q Ports * 1 Inactive 30 Inactive Management VLAN 100 Inactive A Eth1/1/1 200 Inactive A Eth1/1/3-1/1/58 201 Inactive A Eth1/1/2 OS10# If there are access switch ports assigned to the default VLAN, this is a finding.

ℹ️ Check

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: OS10# show vlan Codes: * - Default VLAN, M - Management VLAN, R - Remote Port Mirroring VLANs, @ - Attached to Virtual Network, P - Primary, C - Community, I - Isolated, S - VLAN-Stack VLAN Q: A - Access (Untagged), T - Tagged NUM Status Description Q Ports * 1 Inactive 30 Inactive Management VLAN 100 Inactive A Eth1/1/1 200 Inactive A Eth1/1/3-1/1/58 201 Inactive A Eth1/1/2 OS10# If there are access switch ports assigned to the default VLAN, this is a finding.

✔️ Fix
Remove the assignment of the default VLAN from all access switch ports: OS10(config)# interface range eth1/1/4-1/1/58 OS10(conf-range-eth1/1/4-1/1/58)# switchport mode access OS10(conf-range-eth1/1/4-1/1/58)# switchport access vlan 200