Detections
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CISC-RT-000830 - The Cisco multicast Rendezvous Point (RP) switch must be configured to filter Protocol Independent Multicast (PIM) Register messages received from the Designated switch (DR) for any undesirable multicast groups and sources.

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 register messages are accepted only for authorized multicast groups and sources.

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

Solution

Configure the switch to filter PIM register messages received from a multicast DR for any undesirable multicast groups and sources. The example below will deny any multicast streams for groups 239.5.0.0/16 and allow from only sources x.1.2.6 and x.1.2.7.

Step 1: Configure a route map to filter multicast groups and sources as shown in the example below:

SW1(config)# route-map PIM_REGISTER_FILTER deny 10
SW1(config-route-map)# match ip multicast group 239.5.0.0/16
SW1(config-route-map)# route-map PIM_REGISTER_FILTER permit 20
SW1(config-route-map)# match ip multicast source x.1.2.6/32
SW1(config-route-map)# route-map PIM_REGISTER_FILTER permit 30
SW1(config-route-map)# match ip multicast source x.1.2.7/32
SW1(config-route-map)# route-map PIM_REGISTER_FILTER permit 40
SW1(config-route-map)# match ip multicast group-range 232.0.0.0 to 233.255.255.255
SW1(config-route-map)# route-map PIM_REGISTER_FILTER deny 50
SW1(config-route-map)# match ip multicast source 0.0.0.0/0
SW1(config-route-map)# exit

Step 2: Configure a multicast register policy referencing the configured route map.

SW1(config)# ip pim register-policy PIM_REGISTER_FILTER
SW1(config)# 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-221136r1137930_rule, STIG-ID|CISC-RT-000830, STIG-Legacy|SV-111091, STIG-Legacy|V-101987, Vuln-ID|V-221136

Plugin: Cisco

Control ID: d689b6956472117bdda831e5fe40d4c5e3d9ab00087de7528b4aae2c6dc52648