The Cisco 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.
An XCCDF Rule
Description
<VulnDiscussion>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.</VulnDiscussion><FalsePositives></FalsePositives><FalseNegatives></FalseNegatives><Documentable>false</Documentable><Mitigations></Mitigations><SeverityOverrideGuidance></SeverityOverrideGuidance><PotentialImpacts></PotentialImpacts><ThirdPartyTools></ThirdPartyTools><MitigationControl></MitigationControl><Responsibility></Responsibility><IAControls></IAControls>
- ID
- SV-216785r856446_rule
- Severity
- Low
- References
- Updated
Remediation - Manual Procedure
This requirement is not applicable for the DODIN Backbone.
Configure the router to limit the prefix size on any route advertisement to /24 or the least significant prefixes issued to the customer.
Step 1: Configure a prefix set to not include prefixes are longer than /24.