The Cisco BGP router must be configured to reject inbound route advertisements for any Bogon prefixes.
An XCCDF Rule
Description
<VulnDiscussion>Accepting route advertisements for Bogon prefixes can result in the local autonomous system (AS) becoming a transit for malicious traffic as it will in turn advertise these prefixes to neighbor autonomous systems.</VulnDiscussion><FalsePositives></FalsePositives><FalseNegatives></FalseNegatives><Documentable>false</Documentable><Mitigations></Mitigations><SeverityOverrideGuidance></SeverityOverrideGuidance><PotentialImpacts></PotentialImpacts><ThirdPartyTools></ThirdPartyTools><MitigationControl></MitigationControl><Responsibility></Responsibility><IAControls></IAControls>
- ID
- SV-216777r531087_rule
- Severity
- Medium
- References
- Updated
Remediation - Manual Procedure
Configure the router to reject inbound route advertisements for any Bogon prefixes.
Step 1: Configure a prefix set containing the current Bogon prefixes as shown below.
RP/0/0/CPU0:R2(config)#prefix-set BOGON_PREFIXES
RP/0/0/CPU0:R2(config-pfx)#0.0.0.0/8 le 32,