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The Cisco BGP switch 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 IDVersionRule IDIA ControlsSeverity
V-221026CISC-RT-000520SV-221026r622190_ruleCCI-001368medium
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. It is also possible that a misconfigured or compromised switch within the GIG IP core could redistribute Interior Gateway Protocol (IGP) routes into BGP, thereby leaking internal routes.
STIGDate
Cisco IOS XE Switch RTR Security Technical Implementation Guide2025-05-20

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-221026r622190_chk)

Step 1: Verify that a prefix list has been configured containing prefixes belonging to customers as well as the local AS as shown in the example below: ip prefix-list CE_PREFIX_ADVERTISEMENTS seq 5 permit x.13.1.0/24 le 32 ip prefix-list CE_PREFIX_ADVERTISEMENTS seq 10 permit x.13.2.0/24 le 32 ip prefix-list CE_PREFIX_ADVERTISEMENTS seq 15 permit x.13.3.0/24 le 32 ip prefix-list CE_PREFIX_ADVERTISEMENTS seq 20 permit x.13.4.0/24 le 32 … … … ip prefix-list CE_PREFIX_ADVERTISEMENTS seq 80 deny 0.0.0.0/0 ge 8 Step 2: Verify that the prefix lists has been applied to all CE peers as shown in the example below: router bgp 64512 no synchronization bgp log-neighbor-changes neighbor x.12.4.14 remote-as 64514 neighbor x.12.4.14 prefix-list CE_PREFIX_ADVERTISEMENTS out neighbor x.12.4.16 remote-as 64516 neighbor x.12.4.16 prefix-list CE_PREFIX_ADVERTISEMENTS out If the switch is not configured to reject outbound route advertisements that do not belong to any customers or the local AS, this is a finding.

Fix Text (F-22730r408873_fix)

Step 1: Configure a prefix list for containing all customer and local AS prefixes as shown in the example below: SW1(config)#ip prefix-list CE_PREFIX_ADVERTISEMENTS permit x.13.1.0/24 le 32 SW1(config)#ip prefix-list CE_PREFIX_ADVERTISEMENTS permit x.13.2.0/24 le 32 SW1(config)#ip prefix-list CE_PREFIX_ADVERTISEMENTS permit x.13.3.0/24 le 32 SW1(config)#ip prefix-list CE_PREFIX_ADVERTISEMENTS permit x.13.4.0/24 le 32 … … … SW1(config)#ip prefix-list CE_PREFIX_ADVERTISEMENTS deny 0.0.0.0/0 ge 8 Step 2: Apply the prefix list filter outbound to each CE neighbor as shown in the example. SW1(config)#router bgp 64512 SW1(config-switch)#neighbor x.12.4.14 prefix-list CE_PREFIX_ADVERTISEMENTS out SW1(config-switch)#neighbor x.12.4.16 prefix-list CE_PREFIX_ADVERTISEMENTS out