The BGP router must be configured to reject inbound route advertisements for any prefixes belonging to the local autonomous system (AS).

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-207099	SRG-NET-000018-RTR-000003	SV-207099r604135_rule		Medium

Description
Accepting route advertisements belonging to the local AS can result in traffic looping or being black holed, or at a minimum using a non-optimized path.

STIG	Date
Router Security Requirements Guide	2021-03-16

Details

Check Text ( C-7360r382142_chk )
Review the router configuration to verify that it will reject routes belonging to the local AS. The prefix filter must be referenced inbound on the appropriate BGP neighbor statements. If the router is not configured to reject inbound route advertisements belonging to the local AS, this is a finding.

Fix Text (F-7360r382143_fix)
Ensure all eBGP routers are configured to reject inbound route advertisements for any prefixes belonging to the local AS.