STIGQter: STIG Summary: Arista MLS EOS 4.X Router Security Technical Implementation Guide Version: 2 Release: 2 Benchmark Date: 02 Apr 2025:

The Arista multicast Designated Router (DR) must be configured to filter the Internet Group Management Protocol (IGMP) and Multicast Listener Discovery (MLD) Report messages to allow hosts to join only multicast groups that have been approved by the organization.

DISA Rule

SV-256045r882477_rule

Vulnerability Number

V-256045

Group Title

SRG-NET-000364-RTR-000114

Rule Version

ARST-RT-000660

Severity

CAT III

CCI(s)

• CCI-002403 - Only allow incoming communications from organization-defined authorized sources routed to organization-defined authorized destinations.

Weight

10

Fix Recommendation

Configure the Arista DR to filter the IGMP and MLD report messages to allow hosts to join only multicast groups that have been approved.

Step 1: Configure the ACL to filter the unauthorized IGMP groups.

LEAF-1A(config-if-Et3)#ip access-list FILTER_IGMP
LEAF-1A(config-acl-FILTER_IGMP)# 10 deny igmp 232.0.0.0/8 any
LEAF-1A(config-acl-FILTER_IGMP)# 20 permit ip any any

Step 2: Configure the IGMP filter in IGMP process.

LEAF-1A(config-acl-FILTER_IGMP)#router igmp
LEAF-1A(config-router-igmp)# ip igmp access-group FILTER_IGMP

or

Configure the IGMP filter on internal host-facing interfaces (IGMP process) to filter IGMP.

LEAF-1A(config-router-igmp)#interface ethernet 3
LEAF-1A(config-if-Et3)# ip access-group FILTER_IGMP in

Check Contents

Review the configuration of the Arista DR to verify it is filtering IGMP or MLD report messages, allowing hosts to join only groups that have been approved.

Note: This requirement is only applicable to Source Specific Multicast (SSM) implementation. This requirement is not applicable to Any Source Multicast (ASM) because the filtering is being performed by the Rendezvous Point router.

Step 1: Verify the ACL filters the unauthorized IGMP groups. The ACL below is blocking the IGMP group sourced 232.0.0.0/8. Execute the command "sh ip access-list".

ip access-list FILTER_IGMP
10 deny igmp 232.0.0.0/8 any
20 permit ip any any

Step 2: Verify the ACL is configured on internal host-facing interfaces (IGMP process) to filter IGMP.

router igmp
ip igmp access-group FILTER_IGMP

or

interface ethernet 3
ip access-group FILTER_IGMP

If the Arista DR is not filtering IGMP or MLD report messages, this is a finding.

Vulnerability Number

V-256045

Documentable

False

Rule Version

ARST-RT-000660

Severity Override Guidance

Review the configuration of the Arista DR to verify it is filtering IGMP or MLD report messages, allowing hosts to join only groups that have been approved.

Note: This requirement is only applicable to Source Specific Multicast (SSM) implementation. This requirement is not applicable to Any Source Multicast (ASM) because the filtering is being performed by the Rendezvous Point router.

Step 1: Verify the ACL filters the unauthorized IGMP groups. The ACL below is blocking the IGMP group sourced 232.0.0.0/8. Execute the command "sh ip access-list".

ip access-list FILTER_IGMP
10 deny igmp 232.0.0.0/8 any
20 permit ip any any

Step 2: Verify the ACL is configured on internal host-facing interfaces (IGMP process) to filter IGMP.

router igmp
ip igmp access-group FILTER_IGMP

or

interface ethernet 3
ip access-group FILTER_IGMP

If the Arista DR is not filtering IGMP or MLD report messages, this is a finding.

Check Content Reference

M

Target Key

5513