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V-256022

CAT II (Medium)

The Arista router must be configured with Unicast Reverse Path Forwarding (uRPF) loose mode enabled on all CE-facing interfaces.

Rule ID

SV-256022r882408_rule

STIG

Arista MLS EOS 4.2x Router Security Technical Implementation Guide

Version

V1R1

CCIs

CCI-001097

Discussion

The uRPF feature is a defense against spoofing and denial-of-service (DoS) attacks by verifying if the source address of any ingress packet is reachable. To mitigate attacks that rely on forged source addresses, all provider edge routers must enable uRPF loose mode to guarantee that all packets received from a CE router contain source addresses that are in the route table.

Check Content

Review the Arista router configuration to determine if uRPF loose mode is enabled on all CE-facing interfaces.

To verify the interface configuration uRPF loose mode is enabled on all CE-facing interfaces, execute the command "sh run int Eth YY".

interface Ethernet 3/17/1
ip address 10.10.22.1/30
ip verify unicast source reachable-via any

If uRPF loose mode is not enabled on all CE-facing interfaces, this is a finding.

Fix Text

Enable uRPF loose mode on all CE-facing interfaces.

Configure uRPF loose mode on all CE-facing interfaces.

router(config)#interface Ethernet 3/17/1
router(config-if-Et3/17/1)#ip verify unicast source reachable-via any
router(config-if-Et3/17/1)#end