JUNI-RT-000535 - The Juniper BGP router must be configured to reject route advertisements from CE routers with an originating AS in the AS_PATH attribute that does not belong to that customer - as-path

Information

Verifying the path a route has traversed will ensure that the local AS is not used as a transit network for unauthorized traffic. To ensure that the local AS does not carry any prefixes that do not belong to any customers, all PE routers must be configured to reject routes with an originating AS other than that belonging to the customer.

Solution

Step 1: Configure a policy to filter the AS_PATH as shown in the example below:

[edit policy-options]
set as-path PEER_ASx '^x$'
set policy-statement FILTER_ASx term ALLOW_ASx from as-path PEER_ASx
set policy-statement FILTER_ASx term ALLOW_ASx then accept
set policy-statement FILTER_ASx term ELSE_REJECT then reject

Step 2: Apply the import policy as shown in the example below:

[edit protocols bgp group GROUP_ASx]
set import [FILTER_AS4 FILTER_ROUTES]

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_Juniper_Router_Y24M07_STIG.zip

Item Details

Category: ACCESS CONTROL

References: 800-53|AC-4(8), CAT|III, CCI|CCI-000032, Rule-ID|SV-217059r945855_rule, STIG-ID|JUNI-RT-000535, STIG-Legacy|SV-105143, STIG-Legacy|V-96005, Vuln-ID|V-217059

Plugin: Juniper

Control ID: 02e17472015d7e3aab19b77c296881e3ef8a513d7270f02bdbf472fee4e0e186