The multicast Rendezvous Point (RP) router must be configured to filter Protocol Independent Multicast (PIM) Join messages received from the Designated Router (DR) for any undesirable multicast groups.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-55749	SRG-NET-000019-RTR-000014	SV-70003r3_rule		Low

Description
Real-time multicast traffic can entail multiple large flows of data. An attacker can flood a network segment with multicast packets, over-using the available bandwidth and thereby creating a denial-of-service (DoS) condition. Hence, it is imperative that join messages are only accepted for authorized multicast groups.

STIG	Date
Router Security Requirements Guide	2020-06-30

Details

Check Text ( C-56317r4_chk )
Verify that the RP router is configured to filter PIM register messages. Note: Alternative is to configure all designated routers to filter IGMP Membership Report (a.k.a join) messages received from hosts. If the RP router peering with PIM-SM routers is not configured with a PIM import policy to block registration messages for any undesirable multicast groups and Bogon sources, this is a finding.

Check Text ( C-56317r4_chk )

Verify that the RP router is configured to filter PIM register messages.

Note: Alternative is to configure all designated routers to filter IGMP Membership Report (a.k.a join) messages received from hosts.

If the RP router peering with PIM-SM routers is not configured with a PIM import policy to block registration messages for any undesirable multicast groups and Bogon sources, this is a finding.

Fix Text (F-60621r2_fix)
RP routers that are peering with customer PIM-SM routers must implement a PIM import policy to block join messages for reserved and any undesirable multicast groups.