CISC-RT-000880 - The Cisco multicast Designated switch (DR) must be configured to limit the number of mroute states resulting from Internet Group Management Protocol (IGMP) and Multicast Listener Discovery (MLD) Host Membership Reports.

Information

The current multicast paradigm can let any host join any multicast group at any time by sending an IGMP or MLD membership report to the DR. In a Protocol Independent Multicast (PIM) Sparse Mode network, the DR will send a PIM Join message for the group to the RP.

Without any form of admission control, this can pose a security risk to the entire multicast domain, specifically the multicast switches along the shared tree from the DR to the RP that must maintain the mroute state information for each group join request. Hence, it is imperative that the DR is configured to limit the number of mroute state information that must be maintained to mitigate the risk of IGMP or MLD flooding.

Solution

Configure the DR on a global or interface basis to limit the number of mroute states resulting from IGMP or MLD membership reports.

SW2(config)#int vlan3
SW2(config-if)#ip igmp limit 2

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_Cisco_IOS_Switch_Y24M07_STIG.zip

Item Details

Category: SYSTEM AND COMMUNICATIONS PROTECTION

References: 800-53|SC-5, CAT|II, CCI|CCI-002385, Rule-ID|SV-220466r856246_rule, STIG-ID|CISC-RT-000880, STIG-Legacy|SV-110785, STIG-Legacy|V-101681, Vuln-ID|V-220466

Plugin: Cisco

Control ID: 86dba3df6e54cceb2a5950dbbe7ec91147ba450c9a94e78ed5a8b138791a4566