The Cisco router must be configured to only permit management traffic that ingresses and egresses the out-of-band management (OOBM) interface.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-216773	CISC-RT-000450	SV-216773r531087_rule		Medium

Description
The OOBM access switch will connect to the management interface of the managed network elements. The management interface can be a true OOBM interface or a standard interface functioning as the management interface. In either case, the management interface of the managed network element will be directly connected to the OOBM network. An OOBM interface does not forward transit traffic, thereby providing complete separation of production and management traffic. Since all management traffic is immediately forwarded into the management network, it is not exposed to possible tampering. The separation also ensures that congestion or failures in the managed network do not affect the management of the device. If the device does not have an OOBM port, the interface functioning as the management interface must be configured so that management traffic does not leak into the managed network and that production traffic does not leak into the management network.

Description

The OOBM access switch will connect to the management interface of the managed network elements. The management interface can be a true OOBM interface or a standard interface functioning as the management interface. In either case, the management interface of the managed network element will be directly connected to the OOBM network. An OOBM interface does not forward transit traffic, thereby providing complete separation of production and management traffic. Since all management traffic is immediately forwarded into the management network, it is not exposed to possible tampering. The separation also ensures that congestion or failures in the managed network do not affect the management of the device. If the device does not have an OOBM port, the interface functioning as the management interface must be configured so that management traffic does not leak into the managed network and that production traffic does not leak into the management network.

STIG	Date
Cisco IOS XR Router RTR Security Technical Implementation Guide	2023-02-28

Details

Check Text ( C-18005r288702_chk )
This requirement is only applicable where management access to the router is via an OOBM interface which is not a true OOBM interface. Step 1: Verify that the managed interface has an inbound and outbound ACL configured. interface MgmtEth0/0/CPU0/0 ipv4 address 10.1.13.4 255.255.255.0 ipv4 access-group INGRESS_MANAGEMENT_ACL ingress ipv4 access-group EGRESS_MANAGEMENT_ACL egress Step 2: Verify that the ingress ACL only allows management and ICMP traffic. ipv4 access-list INGRESS_MANAGEMENT_ACL 10 permit tcp any host 10.11.1.22 eq tacacs 20 permit tcp any host 10.11.1.22 eq ssh 30 permit udp any host 10.11.1.22 eq snmp 40 permit udp any host 10.11.1.22 eq snmptrap 50 permit udp any host 10.11.1.22 eq ntp 60 permit icmp any host 10.11.1.22 70 deny ipv4 any any log-input Step 3: Verify that the egress ACL blocks any transit traffic. ipv4 access-list EGRESS_MANAGEMENT_ACL 10 deny ipv4 any any log-input Note: On Cisco routers, local generated packets are not inspected by outgoing interface access-lists. Hence, the above configuration would simply drop any packets not generated by the router; hence, blocking any transit traffic. If the router does not restrict traffic that ingresses and egresses the management interface, this is a finding.

Check Text ( C-18005r288702_chk )

This requirement is only applicable where management access to the router is via an OOBM interface which is not a true OOBM interface.

Step 1: Verify that the managed interface has an inbound and outbound ACL configured.

interface MgmtEth0/0/CPU0/0
ipv4 address 10.1.13.4 255.255.255.0
ipv4 access-group INGRESS_MANAGEMENT_ACL ingress
ipv4 access-group EGRESS_MANAGEMENT_ACL egress

Step 2: Verify that the ingress ACL only allows management and ICMP traffic.

ipv4 access-list INGRESS_MANAGEMENT_ACL
10 permit tcp any host 10.11.1.22 eq tacacs
20 permit tcp any host 10.11.1.22 eq ssh
30 permit udp any host 10.11.1.22 eq snmp
40 permit udp any host 10.11.1.22 eq snmptrap
50 permit udp any host 10.11.1.22 eq ntp
60 permit icmp any host 10.11.1.22
70 deny ipv4 any any log-input

Step 3: Verify that the egress ACL blocks any transit traffic.

ipv4 access-list EGRESS_MANAGEMENT_ACL
10 deny ipv4 any any log-input

Note: On Cisco routers, local generated packets are not inspected by outgoing interface access-lists. Hence, the above configuration would simply drop any packets not generated by the router; hence, blocking any transit traffic.

If the router does not restrict traffic that ingresses and egresses the management interface, this is a finding.

Fix Text (F-18003r288703_fix)
If the management interface is not a dedicated OOBM interface, it must be configured with both an ingress and egress ACL. Step 1: Configure an ingress ACL a shown in the example below. RP/0/0/CPU0:R2(config)#Ipv4 access-list INGRESS_MANAGEMENT_ACL RP/0/0/CPU0:R2(config-ipv4-acl)#permit tcp any host 10.11.1.22 eq tacacs RP/0/0/CPU0:R2(config-ipv4-acl)#permit tcp any host 10.11.1.22 eq 22 RP/0/0/CPU0:R2(config-ipv4-acl)#permit udp any host 10.11.1.22 eq snmp RP/0/0/CPU0:R2(config-ipv4-acl)#permit udp any host 10.11.1.22 eq snmptrap RP/0/0/CPU0:R2(config-ipv4-acl)#permit udp any host 10.11.1.22 eq ntp RP/0/0/CPU0:R2(config-ipv4-acl)#permit icmp any host 10.11.1.22 RP/0/0/CPU0:R2(config-ipv4-acl)#deny ip any any log-input RP/0/0/CPU0:R2(config-ipv4-acl)#exit Step 2: Configure an egress ACL a shown in the example below. RP/0/0/CPU0:R2(config)#Ipv4 access-list EGRESS_MANAGEMENT_ACL RP/0/0/CPU0:R2(config-ipv4-acl)#deny ip any any log-input RP/0/0/CPU0:R2(config-ipv4-acl)#exit Step 3: Apply the ACLs to the OOBM interfaces. RP/0/0/CPU0:R2(config)#int MgmtEth0/0/CPU0/0 RP/0/0/CPU0:R2(config-if)#ipv4 access-group INGRESS_MANAGEMENT_ACL ingress RP/0/0/CPU0:R2(config-if)#ipv4 access-group EGRESS_MANAGEMENT_ACL egress

Fix Text (F-18003r288703_fix)

If the management interface is not a dedicated OOBM interface, it must be configured with both an ingress and egress ACL.

Step 1: Configure an ingress ACL a shown in the example below.

RP/0/0/CPU0:R2(config)#Ipv4 access-list INGRESS_MANAGEMENT_ACL
RP/0/0/CPU0:R2(config-ipv4-acl)#permit tcp any host 10.11.1.22 eq tacacs
RP/0/0/CPU0:R2(config-ipv4-acl)#permit tcp any host 10.11.1.22 eq 22
RP/0/0/CPU0:R2(config-ipv4-acl)#permit udp any host 10.11.1.22 eq snmp
RP/0/0/CPU0:R2(config-ipv4-acl)#permit udp any host 10.11.1.22 eq snmptrap
RP/0/0/CPU0:R2(config-ipv4-acl)#permit udp any host 10.11.1.22 eq ntp
RP/0/0/CPU0:R2(config-ipv4-acl)#permit icmp any host 10.11.1.22
RP/0/0/CPU0:R2(config-ipv4-acl)#deny ip any any log-input
RP/0/0/CPU0:R2(config-ipv4-acl)#exit

Step 2: Configure an egress ACL a shown in the example below.

RP/0/0/CPU0:R2(config)#Ipv4 access-list EGRESS_MANAGEMENT_ACL
RP/0/0/CPU0:R2(config-ipv4-acl)#deny ip any any log-input
RP/0/0/CPU0:R2(config-ipv4-acl)#exit

Step 3: Apply the ACLs to the OOBM interfaces.

RP/0/0/CPU0:R2(config)#int MgmtEth0/0/CPU0/0
RP/0/0/CPU0:R2(config-if)#ipv4 access-group INGRESS_MANAGEMENT_ACL ingress
RP/0/0/CPU0:R2(config-if)#ipv4 access-group EGRESS_MANAGEMENT_ACL egress