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

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-207140	SRG-NET-000205-RTR-000008	SV-207140r604135_rule		Medium

Description
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.

STIG	Date
Router Security Requirements Guide	2021-03-16

Details

Check Text ( C-7401r382358_chk )
Review the router configuration to determine if uRPF loose mode is enabled on all CE-facing interfaces. If uRPF loose mode is not enabled on all CE-facing interfaces, this is a finding.

Fix Text (F-7401r382359_fix)
Enable uRPF loose mode on all CE-facing interfaces.