The Cisco PE switch must be configured to have each Virtual Routing and Forwarding (VRF) instance bound to the appropriate physical or logical interfaces to maintain traffic separation between all MPLS L3VPNs.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-221117	CISC-RT-000630	SV-221117r622190_rule		High

Description
The primary security model for an MPLS L3VPN infrastructure is traffic separation. The service provider must guarantee the customer that traffic from one VPN does not leak into another VPN or into the core, and that core traffic must not leak into any VPN. Hence, it is imperative that each CE-facing interface can only be associated to one VRF—that alone is the fundamental framework for traffic separation.

Description

The primary security model for an MPLS L3VPN infrastructure is traffic separation. The service provider must guarantee the customer that traffic from one VPN does not leak into another VPN or into the core, and that core traffic must not leak into any VPN. Hence, it is imperative that each CE-facing interface can only be associated to one VRF—that alone is the fundamental framework for traffic separation.

STIG	Date
Cisco NX OS Switch RTR Security Technical Implementation Guide	2023-02-15

Details

Check Text ( C-22832r409840_chk )
Step 1: Review the design plan for deploying MPLS/L3VPN. Step 2: Review all CE-facing interfaces and verify that the proper VRF is defined via the ip vrf forwarding command. In the example below, customer 1 is bound to interface Ethernet2/1, while customer 2 is bound to Ethernet2/2. interface Ethernet2/1 no switchport vrf member CUST1 ip address x.2.22.3/24 interface Ethernet2/2 no switchport vrf member CUST2 ip address x.2.8.4/24 If any VRFs are not bound to the appropriate physical or logical interface, this is a finding.

Check Text ( C-22832r409840_chk )

Step 1: Review the design plan for deploying MPLS/L3VPN.

Step 2: Review all CE-facing interfaces and verify that the proper VRF is defined via the ip vrf forwarding command. In the example below, customer 1 is bound to interface Ethernet2/1, while customer 2 is bound to Ethernet2/2.

interface Ethernet2/1
no switchport
vrf member CUST1
ip address x.2.22.3/24

interface Ethernet2/2
no switchport
vrf member CUST2
ip address x.2.8.4/24

If any VRFs are not bound to the appropriate physical or logical interface, this is a finding.

Fix Text (F-22821r409841_fix)
Configure the PE switch to have each VRF bound to the appropriate physical or logical interfaces to maintain traffic separation between all MPLS L3VPNs.