Detections
Analytics

CISC-RT-000930 - The Cisco Multicast Source Discovery Protocol (MSDP) switch must be configured to filter source-active multicast advertisements to external MSDP peers to avoid global visibility of local-only multicast sources and groups.

Information

To avoid global visibility of local information, there are a number of source-group (S, G) states in a PIM-SM domain that must not be leaked to another domain, such as multicast sources with private address, administratively scoped multicast addresses, and the auto-RP groups (224.0.1.39 and 224.0.1.40).

Allowing a multicast distribution tree, local to the core, to extend beyond its boundary could enable local multicast traffic to leak into other autonomous systems and customer networks.

Solution

Configure the switch with an export policy avoid global visibility of local multicast (S, G) states. The example below will prevent exporting multicast active sources belonging to the private network.

SW1(config)#ip access-list extended OUTBOUND_MSDP_SA_FILTER
SW1(config-ext-nacl)#deny ip 10.0.0.0 0.255.255.255 any
SW1(config-ext-nacl)#permit ip any any
SW1(config-ext-nacl)#exit
SW1(config)#ip msdp sa-filter in x.1.28.2 list OUTBOUND_MSDP_SA_FILTER

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_Cisco_IOS-XE_Switch_Y26M04_STIG.zip

Item Details

Category: ACCESS CONTROL

References: 800-53|AC-4, CAT|III, CCI|CCI-001368, Rule-ID|SV-221067r1137902_rule, STIG-ID|CISC-RT-000930, STIG-Legacy|SV-110955, STIG-Legacy|V-101851, Vuln-ID|V-221067

Plugin: Cisco

Control ID: fd54050242d9de1e062be6c914e775f92fcb9d099b29f70ad0422ef2a7c2f49d