The Nokia Border Gateway Protocol (BGP) router must be configured to reject outbound route advertisements for any prefixes that do not belong to any customers or the local autonomous system (AS).
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-283904 | NOKI-RT-000930 | SV-283904r1204034_rule | CCI-001368 | medium |
| Description | ||||
| Advertisement of routes by an autonomous system for networks that do not belong to any of its customers pulls traffic away from the authorized network. This causes a denial of service (DoS) on the network that allocated the block of addresses and may cause a DoS on the network that is inadvertently advertising it as the originator. A misconfigured or compromised router within the Department of Defense Information Network (DODIN) IP core could redistribute Interior Gateway Protocol (IGP) routes into BGP, thereby leaking internal routes. | ||||
| STIG | Date | |||
| Nokia Service Router OS 25.x Router Security Technical Implementation Guide | 2026-06-15 | |||
Details
Check Text (C-283904r1204034_chk)
This requirement is not applicable for the DODIN Backbone.
Review the router configuration to verify a filter is defined to only advertise routes for prefixes that belong to any customers or the local AS.
Use the command below to view the prefix list:
- show router policy prefix-list "Customer Prefix"
prefix 192.168.100.0/24 prefix-length-range 24-32
prefix 192.168.200.0/24 prefix-length-range 24-32
Use the command below to view the policy statement:
- show router policy "Advertise Customer"
entry 10
from
prefix-list "Advertise Customer"
exit
action accept
exit
exit
default-action drop
exit
Use the command below to verify the policy is applied to the eBGP group:
- show router bgp group "eBGP" detail | match "Export Policy"
Export Policy : Advertise Customer
If the router is not configured to reject outbound route advertisements that belong to any customers or the local AS, this is a finding.
Fix Text (F-88374r1203960_fix)
Configure all eBGP routers to filter outbound route advertisements for prefixes that are not allocated to or belong to any customer or the local AS.
Create a prefix list using the configuration below:
- config>router>policy-options# begin
- config>router>policy-options# prefix-list "Customer Prefix"
- config>router>policy-options>prefix-list$ prefix 192.168.100.0/24 prefix-length-range 24-32
- config>router>policy-options>prefix-list$ prefix 192.168.200.0/24 prefix-length-range 24-32
- config>router>policy-options>prefix-list$ exit
Create a policy statement using the configuration below:
- config>router>policy-options# policy-statement "Advertise Customer"
- config>router>policy-options>policy-statement$ entry 10
- config>router>policy-options>policy-statement>entry$ from prefix-list "Customer Prefix"
- config>router>policy-options>policy-statement>entry$ action accept
- config>router>policy-options>policy-statement>entry>action$ exit
- router>policy-options>policy-statement$ default-action reject
- config>router>policy-options>policy-statement$ exit
- config>router>policy-options# commit
- config>router>policy-options# exit
Apply the routing policy to the BGP neighbor using the configuration below:
- configure router bgp group "eBGP" export "Advertise Customer"