STIGQter: STIG Summary: Cisco NX-OS Switch RTR Security Technical Implementation Guide Version: 2 Release: 1 Benchmark Date: 23 Apr 2021:

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

DISA Rule

SV-221136r622190_rule

Vulnerability Number

V-221136

Group Title

SRG-NET-000019-RTR-000013

Rule Version

CISC-RT-000830

Severity

CAT III

CCI(s)

• CCI-001414 - The information system enforces approved authorizations for controlling the flow of information between interconnected systems based on organization-defined information flow control policies.

Weight

10

Fix Recommendation

Configure the switch to filter PIM register messages received from a multicast DR for any undesirable multicast groups and sources. The example below will deny any multicast streams for groups 239.5.0.0/16 and allow from only sources x.1.2.6 and x.1.2.7.

Step 1: Configure a route map to filter multicast groups and sources as shown in the example below:

SW1(config)# route-map PIM_REGISTER_FILTER deny 10
SW1(config-route-map)# match ip multicast group 239.5.0.0/16
SW1(config-route-map)# route-map PIM_REGISTER_FILTER permit 20
SW1(config-route-map)# match ip multicast source x.1.2.6/32
SW1(config-route-map)# route-map PIM_REGISTER_FILTER permit 30
SW1(config-route-map)# match ip multicast source x.1.2.7/32
SW1(config-route-map)# route-map PIM_REGISTER_FILTER permit 40
SW1(config-route-map)# match ip multicast group-range 232.0.0.0 to 233.255.255.255
SW1(config-route-map)# route-map PIM_REGISTER_FILTER deny 50
SW1(config-route-map)# match ip multicast source 0.0.0.0/0
SW1(config-route-map)# exit

Step 2: Configure a multicast register policy referencing the configured route map.

SW1(config)# ip pim register-policy PIM_REGISTER_FILTER
SW1(config)# end

Check Contents

Verify that the RP switch is configured to filter PIM register messages. The example below will deny any multicast streams for groups 239.5.0.0/16 and allow from only sources x.1.2.6 and x.1.2.7.

ip pim register-policy PIM_REGISTER_FILTER
…
…
…
route-map PIM_REGISTER_FILTER deny 10
match ip multicast group 239.5.0.0/16
route-map PIM_REGISTER_FILTER permit 20
match ip multicast source x.1.2.6/32
route-map PIM_REGISTER_FILTER permit 30
match ip multicast source x.1.2.7/32
route-map PIM_REGISTER_FILTER permit 40
match ip multicast group-range 232.0.0.0 to 233.255.255.255
route-map PIM_REGISTER_FILTER deny 50
match ip multicast source 0.0.0.0/0

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

Vulnerability Number

V-221136

Documentable

False

Rule Version

CISC-RT-000830

Severity Override Guidance

Verify that the RP switch is configured to filter PIM register messages. The example below will deny any multicast streams for groups 239.5.0.0/16 and allow from only sources x.1.2.6 and x.1.2.7.

ip pim register-policy PIM_REGISTER_FILTER
…
…
…
route-map PIM_REGISTER_FILTER deny 10
match ip multicast group 239.5.0.0/16
route-map PIM_REGISTER_FILTER permit 20
match ip multicast source x.1.2.6/32
route-map PIM_REGISTER_FILTER permit 30
match ip multicast source x.1.2.7/32
route-map PIM_REGISTER_FILTER permit 40
match ip multicast group-range 232.0.0.0 to 233.255.255.255
route-map PIM_REGISTER_FILTER deny 50
match ip multicast source 0.0.0.0/0

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

Check Content Reference

M

Target Key

4075

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