V-217070

Discussion

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 router advertises a virtual circuit label mapping that is used as part of the label stack imposed on the frames by the ingress PE router during packet forwarding. Authentication provides protection against spoofed TCP segments that can be introduced into the LDP sessions.

Check Content

Review the router configuration to determine if LDP messages are being authenticated for the targeted LDP sessions. In the example below, the PE router is LDP peering with remote PE 8.8.8.8.

    ldp {
        interface ge-0/1/0.0;
        interface ge-0/1/1.0;
        session 8.8.8.8 {
            authentication-algorithm hmac-sha-1-96;
            authentication-key-chain LDP_KEY;
        }
    }

If authentication is not being used for the LDP targeted sessions using a FIPS-approved message authentication code algorithm, this is a finding.