The PE router must be configured to have each Virtual Routing and Forwarding (VRF) instance with the appropriate Route Target (RT).

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-256053	ARST-RT-000740	SV-256053r882501_rule		High

Description
The primary security model for an MPLS L3VPN as well as a VRF-lite infrastructure is traffic separation. Each interface can only be associated to one VRF, which is the fundamental framework for traffic separation. Forwarding decisions are made based on the routing table belonging to the VRF. Control of what routes are imported into or exported from a VRF is based on the RT. It is critical that traffic does not leak from one COI tenant or L3VPN to another; hence, it is imperative that the correct RT is configured for each VRF.

Description

The primary security model for an MPLS L3VPN as well as a VRF-lite infrastructure is traffic separation. Each interface can only be associated to one VRF, which is the fundamental framework for traffic separation. Forwarding decisions are made based on the routing table belonging to the VRF. Control of what routes are imported into or exported from a VRF is based on the RT. It is critical that traffic does not leak from one COI tenant or L3VPN to another; hence, it is imperative that the correct RT is configured for each VRF.

STIG	Date
Arista MLS EOS 4.2x Router Security Technical Implementation Guide	2023-01-17

Details

Check Text ( C-59729r882499_chk )
Verify the correct RT is configured for each VRF. Review the design plan for MPLS/L3VPN and VRF-lite to determine what RTs have been assigned for each VRF. Review the route-target import, route-target, or route-target export statements under each configured VRF and verify the correct RTs have been defined for each VRF. To verify the correct RTs have been defined for each VRF on a PE router, execute the command "sh run sec router bgp". router bgp 65000 vrf PROD rd 200:200 route-target import vpn-ipv4 200:200 route-target export vpn-ipv4 200:200 Note: Import and export route-maps are normally used when finer granularity is required. If VRFs are configured with the wrong RT, this is a finding.

Check Text ( C-59729r882499_chk )

Verify the correct RT is configured for each VRF.

Review the design plan for MPLS/L3VPN and VRF-lite to determine what RTs have been assigned for each VRF.

Review the route-target import, route-target, or route-target export statements under each configured VRF and verify the correct RTs have been defined for each VRF.

To verify the correct RTs have been defined for each VRF on a PE router, execute the command "sh run sec router bgp".

router bgp 65000
vrf PROD
rd 200:200
route-target import vpn-ipv4 200:200
route-target export vpn-ipv4 200:200

Note: Import and export route-maps are normally used when finer granularity is required.

If VRFs are configured with the wrong RT, this is a finding.

Fix Text (F-59672r882500_fix)
Configure all J-PE Arista routers to have the correct VRF defined with the appropriate RT. Configure the route-target's for import and export. PE11(config)#router bgp 65000 PE11(config-router-bgp)#vrf PROD PE11(config-router-bgp-vrf-PROD)#rd 200:200 PE11(config-router-bgp-vrf-PROD)#route-target import vpn-ipv4 200:200 PE11(config-router-bgp-vrf-PROD)#route-target export vpn-ipv4 200:200