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-207157r856641_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.
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.