Detections
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CISC-RT-000840 - The Cisco multicast Rendezvous Point (RP) switch must be configured to filter Protocol Independent Multicast (PIM) Join messages received from the Designated Cisco switch (DR) for any undesirable multicast groups.

Information

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.

NOTE: Nessus has provided the target output to assist in reviewing the benchmark to ensure target compliance.

Solution

Configure the RP to filter PIM join messages for any undesirable multicast groups as shown in the example below:

Step 1: Configure a PIM Join filter as shown in the example below:

SW1(config)# route-map PIM_JOIN_FILTER deny
SW1(config-route-map)# match ip multicast group 239.8.0.0/8
SW1(config-route-map)# route-map PIM_JOIN_FILTER permit 20
SW1(config-route-map)# match ip multicast group 224.0.0.0/4
SW1(config-route-map)# exit

Step 2: Apply the PIM Join filter to the appropriate interfaces.

SW1(config)# int e2/1
SW1(config-if)# ip pim jp-policy PIM_JOIN_FILTER in
SW1(config-if)# end

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_Cisco_NX-OS_Switch_Y26M04_STIG.zip

Item Details

Category: ACCESS CONTROL

References: 800-53|AC-4, CAT|III, CCI|CCI-001414, Rule-ID|SV-221137r1137932_rule, STIG-ID|CISC-RT-000840, STIG-Legacy|SV-111167, STIG-Legacy|V-102211, Vuln-ID|V-221137

Plugin: Cisco

Control ID: 6f974bf72fdf318541ddb78abf0da063b64825a217a8587f98d28521fa0c1164