STIGQter 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 Source Discovery Protocol (MSDP) router must be configured to only accept MSDP packets from known MSDP peers.

DISA Rule

SV-256047r882483_rule

Vulnerability Number

V-256047

Group Title

SRG-NET-000364-RTR-000116

Rule Version

ARST-RT-000680

Severity

CAT II

CCI(s)

Weight

10

Fix Recommendation

Ensure the receive path or interface filter for all Arista MSDP routers only accepts MSDP packets from known MSDP peers.

Step 1: Configure the MSDP peers.

LEAF-1A(config)#router msdp
LEAF-1A(config-router-msdp)# peer 10.11.12.2
LEAF-1A(config-router-msdp)# peer 10.22.12.2

Step 2: Configure the access-list inbound on MSDP peering interfaces. MSDP uses TCP port 639.

LEAF-1A(config-router-msdp-peer-10.22.12.2)#ip access-list MSDP_FILTER
LEAF-1A(config-acl-MSDP_FILTER)# 10 permit tcp host 10.1.12.2 host 10.11.17.9 eq 639
LEAF-1A(config-acl-MSDP_FILTER)# 20 permit udp host 10.1.12.2 host 10.11.17.9 eq 500
LEAF-1A(config-acl-MSDP_FILTER)# 30 permit udp 10.11.17.9 eq 500 host 10.1.12.2
LEAF-1A(config-acl-MSDP_FILTER)# 40 deny ip any any log

Step 3: Apply the ACL on the interface.

LEAF-1A(config-acl-MSDP_FILTER)#interface ethernet 3
LEAF-1A(config-if-Et3)# ip access-group MSDP_FILTER in

Check Contents

Review the Arista router configuration to determine if there is a receive path or interface filter to only accept MSDP packets from known MSDP peers.

Step 1: Verify the MSDP peers and the corresponding interfaces.

router msdp
peer 10.11.12.2
!
peer 10.22.12.2

Step 2: Verify the access-list is configured inbound on MSDP peering interfaces. MSDP uses TCP port 639. Execute the command "sh ip access-list".

ip access-list MSDP_FILTER
10 permit tcp host 10.1.12.2 host 10.11.17.9 eq 639
20 permit udp host 10.1.12.2 host 10.11.17.9 eq 500
30 permit udp 10.11.17.9 eq 500 host 10.1.12.2
40 deny ip any any log

Step 3: Verify the ACL is applied on the interface. Execute the command "sh run int ethernet YY".

interface ethernet 3
ip access-group MSDP_FILTER in

If the Arista router is not configured to only accept MSDP packets from known MSDP peers, this is a finding.

Vulnerability Number

V-256047

Documentable

False

Rule Version

ARST-RT-000680

Severity Override Guidance

Review the Arista router configuration to determine if there is a receive path or interface filter to only accept MSDP packets from known MSDP peers.

Step 1: Verify the MSDP peers and the corresponding interfaces.

router msdp
peer 10.11.12.2
!
peer 10.22.12.2

Step 2: Verify the access-list is configured inbound on MSDP peering interfaces. MSDP uses TCP port 639. Execute the command "sh ip access-list".

ip access-list MSDP_FILTER
10 permit tcp host 10.1.12.2 host 10.11.17.9 eq 639
20 permit udp host 10.1.12.2 host 10.11.17.9 eq 500
30 permit udp 10.11.17.9 eq 500 host 10.1.12.2
40 deny ip any any log

Step 3: Verify the ACL is applied on the interface. Execute the command "sh run int ethernet YY".

interface ethernet 3
ip access-group MSDP_FILTER in

If the Arista router is not configured to only accept MSDP packets from known MSDP peers, this is a finding.

Check Content Reference

M

Target Key

5513