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.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-221040	SRG-NET-000343-RTR-000001	CISC-RT-000660	SV-221040r863378_rule	2024-06-06	3

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.

ℹ️ Check
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.

ℹ️ Check

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
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