The BGP router must be configured to limit the prefix size on any inbound route advertisement to /24 or the least significant prefixes issued to the customer.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-207157	SRG-NET-000362-RTR-000118	SV-207157r604135_rule		Low

Description
The effects of prefix de-aggregation can degrade router performance due to the size of routing tables and also result in black-holing legitimate traffic. Initiated by an attacker or a misconfigured router, prefix de-aggregation occurs when the announcement of a large prefix is fragmented into a collection of smaller prefix announcements.

STIG	Date
Router Security Requirements Guide	2021-03-16

Details

Check Text ( C-7418r382499_chk )
This requirement is not applicable for the DODIN Backbone. Review the router configuration to verify that there is a filter to reject inbound route advertisements that are greater than /24 or the least significant prefixes issued to the customer, whichever is larger. If the router is not configured to limit the prefix size on any inbound route advertisement to /24 or the least significant prefixes issued to the customer, this is a finding.

Check Text ( C-7418r382499_chk )

This requirement is not applicable for the DODIN Backbone.

Review the router configuration to verify that there is a filter to reject inbound route advertisements that are greater than /24 or the least significant prefixes issued to the customer, whichever is larger.

If the router is not configured to limit the prefix size on any inbound route advertisement to /24 or the least significant prefixes issued to the customer, this is a finding.

Fix Text (F-7418r382500_fix)
Ensure all eBGP routers are configured to limit the prefix size on any route advertisement to /24 or the least significant prefixes issued to the customer.