STIGQter: STIG Summary: Cisco IOS XE Router RTR Security Technical Implementation Guide Version: 2 Release: 2 Benchmark Date: 23 Apr 2021:

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

DISA Rule

SV-216711r531086_rule

Vulnerability Number

V-216711

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.

R2(config)#ip access-list extended BLOCK_TO_CORE
R2(config-ext-nacl)#deny ip any 10.1.x.0 0.0.255.255 log-input
R2(config-ext-nacl)#exit

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

R2(config)#int R4(config)#int g0/2
R2(config-if)#ip access-group BLOCK_TO_CORE in
R2(config-if)#end

Check Contents

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

interface GigabitEthernet0/2
ip address x.1.12.2 255.255.255.252
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 extended BLOCK_TO_CORE
deny ip any 10.1.x.0 0.0.255.255 log-input
permit ip any any
!

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

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

Vulnerability Number

V-216711

Documentable

False

Rule Version

CISC-RT-000730

Severity Override Guidance

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

interface GigabitEthernet0/2
ip address x.1.12.2 255.255.255.252
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 extended BLOCK_TO_CORE
deny ip any 10.1.x.0 0.0.255.255 log-input
permit ip any any
!

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

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

Check Content Reference

M

Target Key

4028

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