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

The Arista router must be configured to block any traffic that is destined to IP core infrastructure.

DISA Rule

SV-256021r882405_rule

Vulnerability Number

V-256021

Group Title

SRG-NET-000205-RTR-000007

Rule Version

ARST-RT-000400

Severity

CAT I

CCI(s)

• CCI-001097 - Monitor and control communications at the external managed interfaces to the system and at key managed interfaces within the system.

Weight

10

Fix Recommendation

Configure protection for the IP core to be implemented at the edges by blocking any traffic with a destination address assigned to the IP core infrastructure.

Step 1: Configure an ingress ACL to drop any traffic with destination address assigned to the IP core infrastructure.

router(config)#ip access-list DROP_INBOUND
router(config-acl-DROP_INBOUND)#deny ip any 172.16.0.0/16 log
router(config-acl-DROP_INBOUND)#permit icmp any any
router(config-acl-DROP_INBOUND)#permit ip any any
router(config-acl-DROP_INBOUND)#exit

Step 2: Apply the ACL to all CE-facing interfaces inbound to drop all the traffic coming toward the CE.

router(config)#interface Ethernet 2
router(config-if-Et2)#ip access-group DROP_INBOUND in
router(config-if-Et2)#end

Check Contents

Review the Arista router configuration to verify an ingress ACL is applied to all CE-facing interfaces.

Verify the ingress ACL rejects and logs packets destined to the IP core address block.

Note: Internet Control Message Protocol (ICMP) echo requests and traceroutes will be allowed to the edge from external adjacent peers.

Step 1: Verify the ingress ACL is configured to drop any traffic with destination address assigned to the IP core infrastructure. Execute the command "sh ip access-list".

ip access-list DROP_INBOUND
deny ip any 172.16.0.0/16 log
permit icmp any any
permit ip any any

Step 2: To verify the ingress ACL applied to all CE facing interfaces inbound to drop all the traffic coming toward the CE, execute the command "sh run int Eth YY".

interface Ethernet 2
ip access-group DROP_INBOUND in

If the Arista PE router is not configured to block any traffic with a destination address assigned to the IP core infrastructure, this is a finding.

Vulnerability Number

V-256021

Documentable

False

Rule Version

ARST-RT-000400

Severity Override Guidance

Review the Arista router configuration to verify an ingress ACL is applied to all CE-facing interfaces.

Verify the ingress ACL rejects and logs packets destined to the IP core address block.

Note: Internet Control Message Protocol (ICMP) echo requests and traceroutes will be allowed to the edge from external adjacent peers.

Step 1: Verify the ingress ACL is configured to drop any traffic with destination address assigned to the IP core infrastructure. Execute the command "sh ip access-list".

ip access-list DROP_INBOUND
deny ip any 172.16.0.0/16 log
permit icmp any any
permit ip any any

Step 2: To verify the ingress ACL applied to all CE facing interfaces inbound to drop all the traffic coming toward the CE, execute the command "sh run int Eth YY".

interface Ethernet 2
ip access-group DROP_INBOUND in

If the Arista PE router is not configured to block any traffic with a destination address assigned to the IP core infrastructure, this is a finding.

Check Content Reference

M

Target Key

5513