The Cisco perimeter router must be configured to block all outbound management traffic.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-216587	CISC-RT-000390	SV-216587r531085_rule		Medium

Description
For in-band management, the management network must have its own subnet in order to enforce control and access boundaries provided by Layer 3 network nodes, such as routers and firewalls. Management traffic between the managed network elements and the management network is routed via the same links and nodes as that used for production or operational traffic. Safeguards must be implemented to ensure that the management traffic does not leak past the perimeter of the managed network.

Description

For in-band management, the management network must have its own subnet in order to enforce control and access boundaries provided by Layer 3 network nodes, such as routers and firewalls. Management traffic between the managed network elements and the management network is routed via the same links and nodes as that used for production or operational traffic. Safeguards must be implemented to ensure that the management traffic does not leak past the perimeter of the managed network.

STIG	Date
Cisco IOS Router RTR Security Technical Implementation Guide	2022-11-21

Details

Check Text ( C-17822r287139_chk )
This requirement is not applicable for the DODIN Backbone. The perimeter router of the managed network must be configured with an outbound ACL on the egress interface to block all management traffic as shown in the example below. Step 1: Verify that all external interfaces have been configured with an outbound ACL as shown in the example below. interface GigabitEthernet0/2 description link to DISN ip address x.11.1.2 255.255.255.254 ip access-group EXTERNAL_ACL_OUTBOUND out Step 2: Verify that the outbound ACL discards management traffic as shown in the example below. ip access-list extended EXTERNAL_ACL_OUTBOUND deny tcp any any eq tacacs log-input deny tcp any any eq 22 log-input deny udp any any eq snmp log-input deny udp any any eq snmptrap log-input deny udp any any eq syslog log-input permit tcp any any eq www log-input deny ip any any log-input If management traffic is not blocked at the perimeter, this is a finding.

Check Text ( C-17822r287139_chk )

This requirement is not applicable for the DODIN Backbone.

The perimeter router of the managed network must be configured with an outbound ACL on the egress interface to block all management traffic as shown in the example below.

Step 1: Verify that all external interfaces have been configured with an outbound ACL as shown in the example below.

interface GigabitEthernet0/2
description link to DISN
ip address x.11.1.2 255.255.255.254
ip access-group EXTERNAL_ACL_OUTBOUND out

Step 2: Verify that the outbound ACL discards management traffic as shown in the example below.

ip access-list extended EXTERNAL_ACL_OUTBOUND
deny tcp any any eq tacacs log-input
deny tcp any any eq 22 log-input
deny udp any any eq snmp log-input
deny udp any any eq snmptrap log-input
deny udp any any eq syslog log-input
permit tcp any any eq www log-input
deny ip any any log-input

If management traffic is not blocked at the perimeter, this is a finding.

Fix Text (F-17818r287140_fix)
This requirement is not applicable for the DODIN Backbone. Configure the perimeter router of the managed network with an outbound ACL on the egress interface to block all management traffic. Step 1: Configure an ACL to block egress management traffic. R5(config)#ip access-list extended EXTERNAL_ACL_OUTBOUND R5(config-ext-nacl)#deny tcp any any eq tacacs log-input R5(config-ext-nacl)#deny tcp any any eq 22 log-input R5(config-ext-nacl)#deny udp any any eq snmp log-input R5(config-ext-nacl)#deny udp any any eq snmptrap log-input R5(config-ext-nacl)#deny udp any any eq syslog log-input R5(config-ext-nacl)#permit tcp any any eq www R5(config-ext-nacl)#deny ip any any log-input R5(config-ext-nacl)#exit Note: Permit commands would be configured to allow applicable outbound traffic. The example above is allowing web traffic. Step 2: Configure the external interfaces with the outbound ACL. R1(config)#int g0/2 R1(config-if)#ip access-group EXTERNAL_ACL_OUTBOUND out

Fix Text (F-17818r287140_fix)

This requirement is not applicable for the DODIN Backbone.

Configure the perimeter router of the managed network with an outbound ACL on the egress interface to block all management traffic.

Step 1: Configure an ACL to block egress management traffic.

R5(config)#ip access-list extended EXTERNAL_ACL_OUTBOUND
R5(config-ext-nacl)#deny tcp any any eq tacacs log-input
R5(config-ext-nacl)#deny tcp any any eq 22 log-input
R5(config-ext-nacl)#deny udp any any eq snmp log-input
R5(config-ext-nacl)#deny udp any any eq snmptrap log-input
R5(config-ext-nacl)#deny udp any any eq syslog log-input
R5(config-ext-nacl)#permit tcp any any eq www
R5(config-ext-nacl)#deny ip any any log-input
R5(config-ext-nacl)#exit

Note: Permit commands would be configured to allow applicable outbound traffic. The example above is allowing web traffic.

Step 2: Configure the external interfaces with the outbound ACL.

R1(config)#int g0/2
R1(config-if)#ip access-group EXTERNAL_ACL_OUTBOUND out