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The Cisco perimeter switch must be configured to filter traffic destined to the enclave in accordance with the guidelines contained in DoD Instruction 8551.1.

Overview

Finding IDVersionRule IDIA ControlsSeverity
V-221092CISC-RT-000320SV-221092r999701_ruleCCI-001097medium
Description
Vulnerability assessments must be reviewed by the System Administrator, and protocols must be approved by the Information Assurance (IA) staff before entering the enclave. ACLs are the first line of defense in a layered security approach. They permit authorized packets and deny unauthorized packets based on port or service type. They enhance the posture of the network by not allowing packets to reach a potential target within the security domain. The lists provided are highly susceptible ports and services that should be blocked or limited as much as possible without adversely affecting customer requirements. Auditing packets attempting to penetrate the network that are stopped by an ACL will allow network administrators to broaden their protective ring and more tightly define the scope of operation. If the perimeter is in a Deny-by-Default posture and what is allowed through the filter is in accordance with DoD Instruction 8551.1, and if the permit rule is explicitly defined with explicit ports and protocols allowed, then all requirements related to PPS being blocked would be satisfied.
STIGDate
Cisco NX OS Switch RTR Security Technical Implementation Guide2026-03-04

Related Frameworks

1 mapping across 5 frameworks
SCF0 mappings

No source states a mapping between these directly.

Also reachable in 3 hops (18) 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.

CFG-02Secure Baseline Configurations
1.00
CRY-01Use of Cryptographic Controls
1.00
CRY-01.1Alternate Physical Protection
1.00
CRY-03Transmission Confidentiality
1.00
CRY-04Transmission Integrity
1.00
CRY-05Encrypting Data At Rest
1.00
DCH-01Data Protection
1.00
IAC-21Least Privilege
1.00
MON-01Continuous Monitoring
1.00
MON-01.1Intrusion Detection & Prevention Systems (IDS & IPS)
1.00

+8 more (top 10 by confidence shown)

NIST 800-530 mappings

No source states a mapping between these directly.

Also reachable in 2 hops (10) 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.

CM-6Configuration Settings
1.00
SC-24Fail in Known State
1.00
SC-47Alternate Communications Paths
1.00
SC-5Denial-of-service Protection
1.00
SC-7Boundary Protection
1.00
SC-7(11)Restrict Incoming Communications Traffic
1.00
SC-7(29)Separate Subnets to Isolate Functions
1.00
SC-7(5)Deny by Default — Allow by Exception
1.00
SI-4System Monitoring
1.00
SI-4(11)Analyze Communications Traffic Anomalies
1.00
NIST 800-1710 mappings

No source states a mapping between these directly.

Also reachable in 3 hops (3) 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.

3.13.1
1.00
3.13.2
1.00
3.13.5
1.00
CCI1 mapping
CCI-001097
1.00
NIST CSF 2.00 mappings

No source states a mapping between these directly.

Also reachable in 3 hops (5) 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-01
1.00
PR.DS-01
1.00
PR.DS-02
1.00
PR.DS-10
1.00
PR.IR-01
1.00

Who does this work

15 NICE work roles and 9 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-221092r999701_chk)

Review the switch configuration to verify that the ingress ACL is in accordance with DoD 8551.1. Step 1: Verify that an inbound ACL is configured on all external interfaces. interface Ethernet2/2 description link to DISN no switchport ip access-group EXTERNAL_ACL in Step 2. Review the inbound ACL to verify that it is filtering traffic in accordance with DoD 8551.1. ip access-list EXTERNAL_ACL 10 permit tcp any any established 20 permit tcp x.11.1.1/32 eq bgp x.11.1.2/32 30 permit tcp x.11.1.1/32 x.11.1.2/32 eq bgp 40 permit icmp x.11.1.1/32 x.11.1.2/32 echo 50 permit icmp x.11.1.1/32 x.11.1.2/32 echo-reply 60 permit tcp any x.11.2.3/32 eq www 70 permit udp x.12.1.9/32 x.12.1.21/32 eq ntp … … < must be in accordance with DoD Instruction 8551.1> … 140 deny ip any any log If the switch does not filter traffic in accordance with the guidelines contained in DoD 8551, this is a finding.

Fix Text (F-22796r409766_fix)

Configure the switch to use an inbound ACL on all external interfaces as shown in the example below to restrict traffic in accordance with the guidelines contained in DOD Instruction 8551.1. SW2(config)# ip access-list EXTERNAL_ACL SW2(config-acl)# permit tcp any any established SW2(config-acl)# permit tcp x.11.1.1/32 eq bgp x.11.1.2/32 SW2(config-acl)# permit tcp x.11.1.1/32 x.11.1.2/32 eq bgp SW2(config-acl)# permit icmp x.11.1.1/32 x.11.1.2/32 echo SW2(config-acl)# permit icmp x.11.1.1/32 x.11.1.2/32 echo-reply SW2(config-acl)# permit tcp any x.11.2.3/32 eq www … … < must be in accordance with DoD Instruction 8551.1> … SW2(config-acl)# deny ip any any log SW2(config-acl)# exit SW1(config)#int e2/2 SW1(config-if)# ip access-group EXTERNAL_ACL in SW1(config-if)# end