STIGQter: STIG Summary: Cisco NX-OS Switch RTR Security Technical Implementation Guide Version: 2 Release: 1 Benchmark Date: 23 Apr 2021:

The Cisco PE switch must be configured to block any traffic that is destined to the IP core infrastructure.

DISA Rule

SV-221126r622190_rule

Vulnerability Number

V-221126

Group Title

SRG-NET-000205-RTR-000007

Rule Version

CISC-RT-000730

Severity

CAT I

CCI(s)

• CCI-001097 - The information system monitors and controls communications at the external boundary of the information system and at key internal boundaries within the system.

Weight

10

Fix Recommendation

Configure protection for the IP core to be implemented at the edges by blocking any traffic with a destination address assigned to the IP core infrastructure.

Step 1: Configure an ingress ACL to discard and log packets destined to the IP core address space.

SW1(config)# ip access-list BLOCK_TO_CORE
SW1(config-acl)# deny ip any 10.1.x.0 0.0.255.255 log
SW1(config-acl)# exit

Step 2: Apply the ACL inbound to all external or CE-facing interfaces.

SW1(config)#int e1/2
SW1(config-if)# ip access-group BLOCK_TO_CORE in
SW1(config-if)# end

Check Contents

Step 1: Review the switch configuration to verify that an ingress ACL is applied to all external or CE-facing interfaces.

interface Ethernet1/2
ip address x.1.12.2/30
ip access-group BLOCK_TO_CORE in

Step 2: Verify that the ingress ACL discards and logs packets destined to the IP core address space.

ip access-list BLOCK_TO_CORE
deny ip any 10.1.x.0 0.0.255.255 log
permit ip any any

Note: Internet Control Message Protocol (ICMP) echo requests and traceroutes will be allowed to the edge from external adjacent neighbors.

If the PE switch is not configured to block any traffic with a destination address assigned to the IP core infrastructure, this is a finding.

Vulnerability Number

V-221126

Documentable

False

Rule Version

CISC-RT-000730

Severity Override Guidance

Step 1: Review the switch configuration to verify that an ingress ACL is applied to all external or CE-facing interfaces.

interface Ethernet1/2
ip address x.1.12.2/30
ip access-group BLOCK_TO_CORE in

Step 2: Verify that the ingress ACL discards and logs packets destined to the IP core address space.

ip access-list BLOCK_TO_CORE
deny ip any 10.1.x.0 0.0.255.255 log
permit ip any any

Note: Internet Control Message Protocol (ICMP) echo requests and traceroutes will be allowed to the edge from external adjacent neighbors.

If the PE switch is not configured to block any traffic with a destination address assigned to the IP core infrastructure, this is a finding.

Check Content Reference

M

Target Key

4075

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