The Arista BGP router must be configured to reject inbound route advertisements from a customer edge (CE) router for prefixes that are not allocated to that customer.
An XCCDF Rule
Description
<VulnDiscussion>As a best practice, a service provider should only accept customer prefixes that have been assigned to that customer and any peering autonomous systems. A multi-homed customer with BGP speaking routers connected to the internet or other external networks could be breached and used to launch a prefix de-aggregation attack. Without ingress route filtering of customers, the effectiveness of such an attack could impact the entire IP core and its customers.</VulnDiscussion><FalsePositives></FalsePositives><FalseNegatives></FalseNegatives><Documentable>false</Documentable><Mitigations></Mitigations><SeverityOverrideGuidance></SeverityOverrideGuidance><PotentialImpacts></PotentialImpacts><ThirdPartyTools></ThirdPartyTools><MitigationControl></MitigationControl><Responsibility></Responsibility><IAControls></IAControls>
- ID
- SV-255990r882312_rule
- Severity
- Medium
- References
- Updated
Remediation - Manual Procedure
Step 1: Configure Arista eBGP routers to reject inbound route advertisements from a CE router for prefixes that are not allocated to that specific customer.
LEAF-1A(config)#ip access-list BGP_Enclave_Gateway_Filter_IN
LEAF-1A(config-acl-BGP_Enclave_Gateway_Filter_IN)# 10 permit ip 172.16.50.0/30 any
LEAF-1A(config-acl-BGP_Enclave_Gateway_Filter_IN)# 20 permit ip 10.1.1.0/24 any
LEAF-1A(config-acl-BGP_Enclave_Gateway_Filter_IN)# 30 permit ip 12.15.4.9/32 any