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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.

An XCCDF Rule

Description

<VulnDiscussion>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.</VulnDiscussion><FalsePositives></FalsePositives><FalseNegatives></FalseNegatives><Documentable>false</Documentable><Mitigations></Mitigations><SeverityOverrideGuidance></SeverityOverrideGuidance><PotentialImpacts></PotentialImpacts><ThirdPartyTools></ThirdPartyTools><MitigationControl></MitigationControl><Responsibility></Responsibility><IAControls></IAControls>

ID
SV-221092r999701_rule
Severity
Medium
References
Updated



Remediation - Manual Procedure

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