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

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-96741	CISC-RT-000390	SV-105879r1_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 XR Router RTR Security Technical Implementation Guide	2019-12-20

Details

Check Text ( C-95577r1_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 has been configured with an outbound ACL as shown in the example below. interface GigabitEthernet0/0/0/2 ipv4 address 10.1.35.3 255.255.255.0 ipv4 access-group EXTERNAL_ACL_OUTBOUND egress Step 2: Verify that the outbound ACL discards management traffic as shown in the example below. ipv4 access-list EXTERNAL_ACL_OUTBOUND 10 deny tcp any any eq tacacs log-input 20 deny tcp any any eq ssh log-input 30 deny udp any any eq snmp log-input 40 deny udp any any eq snmptrap log-input 50 deny udp any any eq syslog log-input 60 permit tcp any any eq www log-input 70 deny ipv4 any any log-input If management traffic is not blocked at the perimeter, this is a finding.

Check Text ( C-95577r1_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 has been configured with an outbound ACL as shown in the example below.

interface GigabitEthernet0/0/0/2
ipv4 address 10.1.35.3 255.255.255.0
ipv4 access-group EXTERNAL_ACL_OUTBOUND egress

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

ipv4 access-list EXTERNAL_ACL_OUTBOUND
10 deny tcp any any eq tacacs log-input
20 deny tcp any any eq ssh log-input
30 deny udp any any eq snmp log-input
40 deny udp any any eq snmptrap log-input
50 deny udp any any eq syslog log-input
60 permit tcp any any eq www log-input
70 deny ipv4 any any log-input

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

Fix Text (F-102419r2_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. RP/0/0/CPU0:R3(config)#Ipv4 access-list EXTERNAL_ACL_OUTBOUND RP/0/0/CPU0:R3(config-ipv4-acl)#deny tcp any any eq tacacs log-input RP/0/0/CPU0:R3(config-ipv4-acl)#deny tcp any any eq 22 log-input RP/0/0/CPU0:R3(config-ipv4-acl)#deny udp any any eq snmp log-input RP/0/0/CPU0:R3(config-ipv4-acl)#deny udp any any eq snmptrap log-input RP/0/0/CPU0:R3(config-ipv4-acl)#deny udp any any eq syslog log-input RP/0/0/CPU0:R3(config-ipv4-acl)#permit tcp any any eq www log-input RP/0/0/CPU0:R3(config-ipv4-acl)#deny ip any any log-input RP/0/0/CPU0:R3(config-ipv4-acl)#end 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. RP/0/0/CPU0:R3(config)#int g0/0/0/2 RP/0/0/CPU0:R3(config-if)#ipv4 access-group EXTERNAL_ACL_OUTBOUND egress

Fix Text (F-102419r2_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.

RP/0/0/CPU0:R3(config)#Ipv4 access-list EXTERNAL_ACL_OUTBOUND
RP/0/0/CPU0:R3(config-ipv4-acl)#deny tcp any any eq tacacs log-input
RP/0/0/CPU0:R3(config-ipv4-acl)#deny tcp any any eq 22 log-input
RP/0/0/CPU0:R3(config-ipv4-acl)#deny udp any any eq snmp log-input
RP/0/0/CPU0:R3(config-ipv4-acl)#deny udp any any eq snmptrap log-input
RP/0/0/CPU0:R3(config-ipv4-acl)#deny udp any any eq syslog log-input
RP/0/0/CPU0:R3(config-ipv4-acl)#permit tcp any any eq www log-input
RP/0/0/CPU0:R3(config-ipv4-acl)#deny ip any any log-input
RP/0/0/CPU0:R3(config-ipv4-acl)#end

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.

RP/0/0/CPU0:R3(config)#int g0/0/0/2
RP/0/0/CPU0:R3(config-if)#ipv4 access-group EXTERNAL_ACL_OUTBOUND egress