The multicast edge router must be configured to establish boundaries for administratively scoped multicast traffic.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-55729	SRG-NET-000019-RTR-000005	SV-69983r3_rule		Low

Description
If multicast traffic is forwarded beyond the intended boundary, it is possible that it can be intercepted by unauthorized or unintended personnel. Administrative scoped multicast addresses are locally assigned and are to be used exclusively by the enterprise network or enclave. Administrative scoped multicast traffic must not cross the enclave perimeter in either direction. Restricting multicast traffic makes it more difficult for a malicious user to access sensitive traffic. Admin-Local scope is encouraged for any multicast traffic within a network intended for network management, as well as for control plane traffic that must reach beyond link-local destinations.

Description

If multicast traffic is forwarded beyond the intended boundary, it is possible that it can be intercepted by unauthorized or unintended personnel. Administrative scoped multicast addresses are locally assigned and are to be used exclusively by the enterprise network or enclave. Administrative scoped multicast traffic must not cross the enclave perimeter in either direction. Restricting multicast traffic makes it more difficult for a malicious user to access sensitive traffic. Admin-Local scope is encouraged for any multicast traffic within a network intended for network management, as well as for control plane traffic that must reach beyond link-local destinations.

STIG	Date
Router Security Requirements Guide	2020-06-30

Details

Check Text ( C-56295r2_chk )
Review the router configuration and verify that admin-scope multicast traffic is blocked at the external edge. If the router is not configured to establish boundaries for administratively scoped multicast traffic, this is a finding.

Fix Text (F-60599r2_fix)
Step 1: Configure the ACL to deny packets with multicast administratively scoped destination addresses. Step 2: Apply the multicast boundary at the appropriate interfaces.