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

The Cisco perimeter switch must be configured to block inbound packets with source Bogon IP address prefixes.

DISA Rule

SV-221010r622190_rule

Vulnerability Number

V-221010

Group Title

SRG-NET-000364-RTR-000110

Rule Version

CISC-RT-000270

Severity

CAT II

CCI(s)

• CCI-002403 - The information system only allows incoming communications from organization-defined authorized sources routed to organization-defined authorized destinations.

Weight

10

Fix Recommendation

Configure the perimeter to block inbound packets with Bogon source addresses.

Step 1: Configure an ACL containing the current Bogon prefixes as shown below:

SW1(config)#ip access-list extended FILTER_PERIMETER
SW1(config-ext-nacl)#deny ip 0.0.0.0 0.255.255.255 any log-input
SW1(config-ext-nacl)#deny ip 10.0.0.0 0.255.255.255 any log-input
SW1(config-ext-nacl)#deny ip 100.64.0.0 0.63.255.255 any log-input
SW1(config-ext-nacl)#deny ip 127.0.0.0 0.255.255.255 any log-input
SW1(config-ext-nacl)#deny ip 169.254.0.0 0.0.255.255 any log-input
SW1(config-ext-nacl)#deny ip 172.16.0.0 0.15.255.255 any log-input
SW1(config-ext-nacl)#deny ip 192.0.0.0 0.0.0.255 any log-input
SW1(config-ext-nacl)#deny ip 192.0.2.0 0.0.0.255 any log-input
SW1(config-ext-nacl)#deny ip 192.168.0.0 0.0.255.255 any log-input
SW1(config-ext-nacl)#deny ip 198.18.0.0 0.1.255.255 any log-input
SW1(config-ext-nacl)#deny ip 198.51.100.0 0.0.0.255 any log-input
SW1(config-ext-nacl)#deny ip 203.0.113.0 0.0.0.255 any log-input
SW1(config-ext-nacl)#deny ip 224.0.0.0 31.255.255.255 any log-input
SW1(config-ext-nacl)#deny ip 240.0.0.0 31.255.255.255 any log-input
SW1(config-ext-nacl)#permit tcp any any established
SW1(config-ext-nacl)#permit tcp host x.12.1.9 host x.12.1.10 eq bgp
SW1(config-ext-nacl)#permit tcp host x.12.1.9 eq bgp host x.12.1.10
SW1(config-ext-nacl)#permit icmp host x.12.1.9 host x.12.1.10 echo
SW1(config-ext-nacl)#permit icmp host x.12.1.9 host x.12.1.10 echo-reply
…
…
…
SW1(config-ext-nacl)#deny ip any any log-input
SW1(config-ext-nacl)#end

Step 2: Apply the ACL inbound on all external interfaces.

SW1(config)#int g0/0
SW1(config-if)#ip access-group FILTER_PERIMETER in
SW1(config-if)#end

Check Contents

Review the switch configuration to verify that an ingress ACL applied to all external interfaces is blocking packets with Bogon source addresses.

Step 1: Verify an ACL has been configured containing the current Bogon prefixes as shown in the example below:

ip access-list extended FILTER_PERIMETER
deny ip 0.0.0.0 0.255.255.255 any log-input
deny ip 10.0.0.0 0.255.255.255 any log-input
deny ip 100.64.0.0 0.63.255.255 any log-input
deny ip 127.0.0.0 0.255.255.255 any log-input
deny ip 169.254.0.0 0.0.255.255 any log-input
deny ip 172.16.0.0 0.15.255.255 any log-input
deny ip 192.0.0.0 0.0.0.255 any log-input
deny ip 192.0.2.0 0.0.0.255 any log-input
deny ip 192.168.0.0 0.0.255.255 any log-input
deny ip 198.18.0.0 0.1.255.255 any log-input
deny ip 198.51.100.0 0.0.0.255 any log-input
deny ip 203.0.113.0 0.0.0.255 any log-input
deny ip 224.0.0.0 31.255.255.255 any log-input
permit tcp any any established
permit tcp host x.12.1.9 host x.12.1.10 eq bgp
permit tcp host x.12.1.9 eq bgp host x.12.1.10
permit icmp host x.12.1.9 host x.12.1.10 echo
permit icmp host x.12.1.9 host x.12.1.10 echo-reply
…
…
…
deny ip any any log-input

Step 2: Verify that the inbound ACL applied to all external interfaces will block all traffic from Bogon source addresses.

interface GigabitEthernet0/1
description Link to DISN
ip address x.12.1.10 255.255.255.254
ip access-group FILTER_PERIMETER in

If the switch is not configured to block inbound packets with source Bogon IP address prefixes, this is a finding.

Vulnerability Number

V-221010

Documentable

False

Rule Version

CISC-RT-000270

Severity Override Guidance

Review the switch configuration to verify that an ingress ACL applied to all external interfaces is blocking packets with Bogon source addresses.

Step 1: Verify an ACL has been configured containing the current Bogon prefixes as shown in the example below:

ip access-list extended FILTER_PERIMETER
deny ip 0.0.0.0 0.255.255.255 any log-input
deny ip 10.0.0.0 0.255.255.255 any log-input
deny ip 100.64.0.0 0.63.255.255 any log-input
deny ip 127.0.0.0 0.255.255.255 any log-input
deny ip 169.254.0.0 0.0.255.255 any log-input
deny ip 172.16.0.0 0.15.255.255 any log-input
deny ip 192.0.0.0 0.0.0.255 any log-input
deny ip 192.0.2.0 0.0.0.255 any log-input
deny ip 192.168.0.0 0.0.255.255 any log-input
deny ip 198.18.0.0 0.1.255.255 any log-input
deny ip 198.51.100.0 0.0.0.255 any log-input
deny ip 203.0.113.0 0.0.0.255 any log-input
deny ip 224.0.0.0 31.255.255.255 any log-input
permit tcp any any established
permit tcp host x.12.1.9 host x.12.1.10 eq bgp
permit tcp host x.12.1.9 eq bgp host x.12.1.10
permit icmp host x.12.1.9 host x.12.1.10 echo
permit icmp host x.12.1.9 host x.12.1.10 echo-reply
…
…
…
deny ip any any log-input

Step 2: Verify that the inbound ACL applied to all external interfaces will block all traffic from Bogon source addresses.

interface GigabitEthernet0/1
description Link to DISN
ip address x.12.1.10 255.255.255.254
ip access-group FILTER_PERIMETER in

If the switch is not configured to block inbound packets with source Bogon IP address prefixes, this is a finding.

Check Content Reference

M

Target Key

4074

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