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.
An XCCDF Rule
Description
<VulnDiscussion>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.</VulnDiscussion><FalsePositives></FalsePositives><FalseNegatives></FalseNegatives><Documentable>false</Documentable><Mitigations></Mitigations><SeverityOverrideGuidance></SeverityOverrideGuidance><PotentialImpacts></PotentialImpacts><ThirdPartyTools></ThirdPartyTools><MitigationControl></MitigationControl><Responsibility></Responsibility><IAControls></IAControls>
- ID
- SV-216812r531087_rule
- Severity
- Low
- References
- Updated
Remediation - Manual Procedure
Configure the RP to filter PIM join messages for any undesirable multicast groups as shown in the example below.
RP/0/0/CPU0:R2(config)#ipv4 access-list FILTER_PIM_JOINS
RP/0/0/CPU0:R2(config-ipv4-acl)#deny 239.8.0.0 0.0.255.255
RP/0/0/CPU0:R2(config-ipv4-acl)#permit any
RP/0/0/CPU0:R2(config-ipv4-acl)#exit