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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.

Overview

Finding IDVersionRule IDIA ControlsSeverity
V-255990ARST-RT-000040SV-255990r882312_ruleCCI-001368medium
Description
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.
STIGDate
Arista MLS EOS 4.X Router Security Technical Implementation Guide2025-02-20

Related Frameworks

1 mapping across 5 frameworks
SCF0 mappings

No source states a mapping between these directly.

Also reachable in 3 hops (17) derived by us, not asserted by any source

Each of these is a route we composed by chaining published mappings. No publisher states a relationship between the two endpoints.

AST-04Network Diagrams & Data Flow Diagrams (DFDs)
1.00
AST-04.2Control Applicability Boundary Graphical Representation
1.00
CFG-02Secure Baseline Configurations
1.00
CRY-01Use of Cryptographic Controls
1.00
DCH-01Data Protection
1.00
DCH-19Geographic Location of Data
1.00
END-01Endpoint Device Management (EDM)
1.00
END-04Malicious Code Protection (Anti-Malware)
1.00
END-06Endpoint File Integrity Monitoring (FIM)
1.00
IAC-21Least Privilege
1.00

+7 more (top 10 by confidence shown)

NIST 800-530 mappings

No source states a mapping between these directly.

Also reachable in 2 hops (42) derived by us, not asserted by any source

Each of these is a route we composed by chaining published mappings. No publisher states a relationship between the two endpoints.

AC-2(1)Automated System Account Management
1.00
AC-2(10)Shared and Group Account Credential Change
1.00
AC-2(2)Automated Temporary and Emergency Account Management
1.00
AC-2(3)Disable Accounts
1.00
AC-2(4)Automated Audit Actions
1.00
AC-3Access Enforcement
1.00
AC-3(7)Role-based Access Control
1.00
AC-4Information Flow Enforcement
1.00
AC-6(10)Prohibit Non-privileged Users from Executing Privileged Functions
1.00
AC-6(9)Log Use of Privileged Functions
1.00

+32 more (top 10 by confidence shown)

NIST 800-1710 mappings

No source states a mapping between these directly.

Also reachable in 3 hops (1) derived by us, not asserted by any source

Each of these is a route we composed by chaining published mappings. No publisher states a relationship between the two endpoints.

3.1.3
1.00
CCI1 mapping
CCI-001368
1.00
NIST CSF 2.00 mappings

No source states a mapping between these directly.

Also reachable in 3 hops (4) derived by us, not asserted by any source

Each of these is a route we composed by chaining published mappings. No publisher states a relationship between the two endpoints.

DE.CM-09
1.00
ID.AM-03
1.00
PR.DS-10
1.00
PR.IR-01
1.00

Who does this work

18 NICE work roles and 10 EC-Council certifications.

This is an inference across published mappings, not a single claim by anyone. This check maps to a control, which maps to a Cybersecurity Framework outcome, which NIST assigns to the work roles below. EC-Council separately maps its certifications to those same roles.

A certification prepares someone for a role. It is not evidence that a holder is qualified, and neither NIST nor EC-Council has stated that any certification here addresses this check.

Work-role assignments published by NIST (NICE Framework Components 2.2.0 and the CSF 2.0 OLIR crosswalk). Certification mappings published by EC-Council.

Details

Check Text (C-255990r882312_chk)

Review the Arista router configuration to verify filters are defined to only accept routes for prefixes that belong to specific customers. The prefix filter must be referenced inbound on the appropriate BGP neighbor statement. Step 1: Verify the Arista router is configured with ip access-list BGP_Enclave_Gateway_Filter_IN. To verify IP access lists are configured, execute the command "show ip access-lists". ip access-list BGP_Enclave_Gateway_Filter_IN 10 permit ip 172.16.50.0/30 any 20 permit ip 10.1.1.0/24 any 30 permit ip 12.15.4.9/32 any 40 deny ip any any log Step 2: Review the route-map and verify it matches the ACL. To verify route maps are configured, execute the command "show route-map". route-map FILTER_INBOUND permit 10 match ip address access-list BGP_Enclave_Gateway_Filter_IN Step 3: Review the BGP configuration to verify the filter is applied inbound to the appropriate BGP neighbor. To verify the BGP config and verify the route map is applied, execute the command "show run | section router bgp". router bgp 65001 neighbor 100.2.1.1 route-map FILTER_INBOUND in If the Arista router is not configured to reject inbound route advertisements from each CE router for prefixes that are not allocated to that customer, this is a finding. Note: Routes to PE-CE links within a VPN are needed for troubleshooting end-to-end connectivity across the MPLS/IP backbone. Hence, these prefixes are an exception to this requirement.

Fix Text (F-59609r882311_fix)

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 LEAF-1A(config-acl-BGP_Enclave_Gateway_Filter_IN)# 40 deny ip any any log Step 2: Configure a route-map to match the ACL. LEAF-1A(config-ip-pfx)#route-map FILTER_INBOUND permit 10 LEAF-1A(config-route-map-FILTER_INBOUND)#match ip address access-list BGP_Enclave_Gateway_Filter_IN Step 3: Configure the route-map to be applied inbound to the appropriate CE customer neighbor. LEAF-1A(config)#router bgp 65001 LEAF-1A(config-router-bgp)#neighbor 100.2.1.1 route-map FILTER_INBOUND in