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V-283865

CAT III (Low)

The Nokia multicast Rendezvous Point (RP) router must be configured to filter Protocol Independent Multicast (PIM) Register messages received from the Designated Router (DR) for any undesirable multicast groups and sources.

Rule ID

SV-283865r1203844_rule

STIG

Nokia Service Router OS 25.x Router Security Technical Implementation Guide

Version

V1R1

CCIs

CCI-001414

Discussion

Real-time multicast traffic can entail multiple large flows of data. An attacker can flood a network segment with multicast packets, overusing the available bandwidth and creating a denial-of-service condition. Hence, it is imperative that register messages are accepted only for authorized multicast groups and sources.

Check Content

Verify the RP router is configured to filter PIM register messages. 

Use the command below to verify the Register Policy:

 - show router pim status | match Policy post-lines 1
Policy
  
    Register Policy               : PIM-JOIN-POLICY

If the RP router peering with PIM-SM routers is not configured with a PIM import policy to block registration messages for any undesirable multicast groups and sources, this is a finding.

Fix Text

Configure the RP router to filter PIM register messages received from a multicast DR for any undesirable multicast groups or sources, as shown in the example below: 

Create a prefix-list:

- configure router policy-options
- config>router>policy-options# begin
- config>router>policy-options# prefix-list PIM-JOIN-GROUP
- config>router>policy-options>prefix-list$ prefix 224.0.0.1/32
- config>router>policy-options>prefix-list$ exit

Create a policy statement:

- config>router>policy-options# policy-statement PIM-JOIN-POLICY
- config>router>policy-options>policy-statement$ entry 10
- config>router>policy-options>policy-statement>entry$ from prefix-list "PIM-JOIN-GROUP"
- config>router>policy-options>policy-statement>entry$ action drop
- config>router>policy-options>policy-statement>entry>action$ exit
- config>router>policy-options>policy-statement>entry$ exit
- config>router>policy-options>policy-statement$ default-action accept
- config>router>policy-options>policy-statement>default-action$ exit
- config>router>policy-options>policy-statement$ exit
- config>router>policy-options# commit
- config>router>policy-options# exit all

Apply the policy: 

- configure router pim import register-policy "PIM-JOIN-POLICY"