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The Cisco BGP switch must be configured to reject inbound route advertisements for any prefixes belonging to the local autonomous system (AS).

Overview

Finding IDVersionRule IDIA ControlsSeverity
V-221024CISC-RT-000500SV-221024r622190_ruleCCI-001368medium
Description
Accepting route advertisements belonging to the local AS can result in traffic looping or being black-holed, or at a minimum, using a non-optimized path.
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-221024r622190_chk)

Review the switch configuration to verify that it will reject routes belonging to the local AS. Step 1: Verify a prefix list has been configured containing prefixes belonging to the local AS. In the example below x.13.1.0/24 is the global address space allocated to the local AS. ip prefix-list PREFIX_FILTER seq 5 deny 0.0.0.0/8 le 32 … … … ip prefix-list PREFIX_FILTER seq 74 deny x.13.1.0/24 le 32 ip prefix-list PREFIX_FILTER seq 75 permit 0.0.0.0/0 ge 8 Step 2: Verify that the prefix list has been applied to all external BGP peers as shown in the example below: router bgp xx no synchronization bgp log-neighbor-changes neighbor x.1.1.9 remote-as yy neighbor x.1.1.9 prefix-list PREFIX_FILTER in neighbor x.2.1.7 remote-as zz neighbor x.2.1.7 prefix-list PREFIX_FILTER in If the switch is not configured to reject inbound route advertisements belonging to the local AS, this is a finding.

Fix Text (F-22728r408867_fix)

Review the switch configuration to verify that it will reject routes belonging to the local AS. Configure the router to reject inbound route advertisements for any prefixes belonging to the local AS. Step 1: Add to the prefix filter list those prefixes belonging to the local autonomous system. SW1(config)#ip prefix-list PREFIX_FILTER seq 74 deny x.13.1.0/24 le 32 Step 2: If not already completed to be compliant with previous requirement, apply the prefix list filter inbound to each external BGP neighbor as shown in the example. SW1(config)#switch bgp xx SW1(config-switch)#neighbor x.1.1.9 prefix-list PREFIX_FILTER in SW1(config-switch)#neighbor x.2.1.7 prefix-list PREFIX_FILTER in SW1(config-switch)#end