CISC-RT-000840 - The Cisco 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.

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.

Solution

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

R2(config)#ip access-list standard PIM_JOIN_FILTER
R2(config-std-nacl)#deny 239.8.0.0 0.0.255.255
R2(config-std-nacl)#permit any
R2(config-std-nacl)#exit
R2(config)#ip pim accept-rp 10.2.2.2 PIM_JOIN_FILTER
R2(config)#end

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_Cisco_IOS-XE_Router_Y24M07_STIG.zip

Item Details

Category: ACCESS CONTROL

References: 800-53|AC-4, CAT|III, CCI|CCI-001414, Rule-ID|SV-216722r531086_rule, STIG-ID|CISC-RT-000840, STIG-Legacy|SV-106155, STIG-Legacy|V-97017, Vuln-ID|V-216722

Plugin: Cisco

Control ID: 1f43397aa1f207211c567abaf97d6d37a949573b2a63e52d4f49d78650a8d8ac