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

The Cisco perimeter switch must be configured to enforce approved authorizations for controlling the flow of information between interconnected networks in accordance with applicable policy.

DISA Rule

SV-220441r622190_rule

Vulnerability Number

V-220441

Group Title

SRG-NET-000019-RTR-000002

Rule Version

CISC-RT-000250

Severity

CAT II

CCI(s)

• CCI-001414 - The information system enforces approved authorizations for controlling the flow of information between interconnected systems based on organization-defined information flow control policies.

Weight

10

Fix Recommendation

Step 1: Configure an ACL to allow or deny traffic as shown in the example below:

R1(config)#ip access-list extended FILTER_PERIMETER
R1(config-ext-nacl)#permit tcp any any established
R1(config-ext-nacl)#permit tcp host x.12.1.9 host x.12.1.10 eq bgp
R1(config-ext-nacl)#permit tcp host x.12.1.9 eq bgp host x.12.1.10
R1(config-ext-nacl)#permit icmp host x.12.1.9 host x.12.1.10 echo
R1(config-ext-nacl)#permit icmp host x.12.1.9 host x.12.1.10 echo-reply
R1(config-ext-nacl)#permit tcp any host x.12.1.22 eq www
R1(config-ext-nacl)#deny ip any any log-input
R1(config-ext-nacl)#exit

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

R2(config)#int g0/0
R1(config-if)#ip access-group FILTER_PERIMETER in
R1(config-if)#end

Check Contents

Review the switch configuration to verify that access control lists (ACLs) are configured to allow or deny traffic for specific source and destination addresses as well as ports and protocols. In the example below, ICMP echo and echo-reply packets are allowed for troubleshooting connectivity. WWW traffic is permitted inbound to the NIPRNet host-facing web server (x.12.1.22).

interface GigabitEthernet0/1
description Link to DISN
ip address x.12.1.10 255.255.255.0
ip access-group FILTER_PERIMETER in
…
…
…
ip access-list extended FILTER_PERIMETER
permit tcp any any established
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
permit tcp any host x.12.1.22 eq www
deny ip any any log-input

If the switch is not configured to enforce approved authorizations for controlling the flow of information between interconnected networks, this is a finding.

Vulnerability Number

V-220441

Documentable

False

Rule Version

CISC-RT-000250

Severity Override Guidance

Review the switch configuration to verify that access control lists (ACLs) are configured to allow or deny traffic for specific source and destination addresses as well as ports and protocols. In the example below, ICMP echo and echo-reply packets are allowed for troubleshooting connectivity. WWW traffic is permitted inbound to the NIPRNet host-facing web server (x.12.1.22).

interface GigabitEthernet0/1
description Link to DISN
ip address x.12.1.10 255.255.255.0
ip access-group FILTER_PERIMETER in
…
…
…
ip access-list extended FILTER_PERIMETER
permit tcp any any established
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
permit tcp any host x.12.1.22 eq www
deny ip any any log-input

If the switch is not configured to enforce approved authorizations for controlling the flow of information between interconnected networks, this is a finding.

Check Content Reference

M

Target Key

4065

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