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-220454
CISC-RT-000660
SV-220454r864159_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.
The Cisco switch is not compliant with this requirement; hence, it is a finding. However, the severity level can be downgraded to a CAT III if the switch is configured to authenticate targeted LDP sessions using MD5 as shown in the configuration example below:
If the switch is not configured to authenticate targeted LDP sessions using MD5, the finding will remain as a CAT II.
Fix Text (F-22158r508442_fix)
The severity level can be downgraded to a CAT III if the switch is configured to authenticate targeted LDP sessions using MD5 as shown in the example below: