The Cisco PE switch providing MPLS Layer 2 Virtual Private Network (L2VPN) services must be configured to authenticate targeted Label Distribution Protocol (LDP) sessions used to exchange virtual circuit (VC) information using a FIPS-approved message authentication code algorithm.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-221040	CISC-RT-000660	SV-221040r863378_rule		Medium

Description
LDP provides the signaling required for setting up and tearing down pseudowires (virtual circuits used to transport Layer 2 frames) across an MPLS IP core network. Using a targeted LDP session, each PE switch advertises a virtual circuit label mapping that is used as part of the label stack imposed on the frames by the ingress PE switch during packet forwarding. Authentication provides protection against spoofed TCP segments that can be introduced into the LDP sessions.

Description

LDP provides the signaling required for setting up and tearing down pseudowires (virtual circuits used to transport Layer 2 frames) across an MPLS IP core network. Using a targeted LDP session, each PE switch advertises a virtual circuit label mapping that is used as part of the label stack imposed on the frames by the ingress PE switch during packet forwarding. Authentication provides protection against spoofed TCP segments that can be introduced into the LDP sessions.

STIG	Date
Cisco IOS XE Switch RTR Security Technical Implementation Guide	2024-06-06

Details

Check Text ( C-22755r507597_chk )
The Cisco switch is not compliant with this requirement; hence, it is a finding. However, the severity level can be downgraded to a category 3 if the switch is configured to authenticate targeted LDP sessions using MD5 as shown in the configuration example below: mpls ldp neighbor 10.1.1.2 password xxxxxxx mpls label protocol ldp If the switch is not configured to authenticate targeted LDP sessions using MD5, the finding will remain as a CAT II.

Check Text ( C-22755r507597_chk )

The Cisco switch is not compliant with this requirement; hence, it is a finding. However, the severity level can be downgraded to a category 3 if the switch is configured to authenticate targeted LDP sessions using MD5 as shown in the configuration example below:

mpls ldp neighbor 10.1.1.2 password xxxxxxx
mpls label protocol ldp

If the switch is not configured to authenticate targeted LDP sessions using MD5, the finding will remain as a CAT II.

Fix Text (F-22744r507598_fix)
The severity level can be downgraded to a category 3 if the switch is configured to authenticate targeted LDP sessions using MD5 as shown in the example below: SW1(config)#mpls ldp neighbor 10.1.1.2 password xxxxxxxx