Management network traffic is leaking into the managed network.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-17819	NET0989	SV-19305r1_rule		Medium

Description
If the gateway router is not a dedicated device for the OOBM network, several safeguards must be implemented for containment of management and production traffic boundaries. To provide separation, access control lists or filters must be configured to block any traffic from the management network destined for the managed network’s production address spaces.

STIG	Date
Perimeter L3 Switch Security Technical Implementation Guide - Cisco	2018-11-28

Details

Check Text ( C-20206r1_chk )
Examine the ingress filter on the OOBM interface of the gateway router to verify that traffic is only destined to the local management address space. In the example configurations below, the 10.1.1.0/24 is the local management network address space at the enclave or managed network and 10.2.2.0/24 is the management network address space at the NOC. IOS interface Serial0/0 description to_OOBM_Backbone ip address 10.1.20.3 255.255.255.0 ip access-group 100 in ip access-group 101 out interface Fastethernet 0/0 description Enclave_Management_LAN ip address 10.1.1.2 255.255.255.0 interface Fastethernet 0/1 description to_our_ServiceNet ip address 172.20.5.2 255.255.255.0 interface Fastethernet 0/2 description to_our_PrivateNet ip address 172.20.4.2 255.255.255.0 ! access-list 100 permit ip 10.2.2.0 0.0.0.255 10.1.1.0 0.0.0.255 access-list 100 deny ip any any log

Check Text ( C-20206r1_chk )

Examine the ingress filter on the OOBM interface of the gateway router to verify that traffic is only destined to the local management address space. In the example configurations below, the 10.1.1.0/24 is the local management network address space at the enclave or managed network and 10.2.2.0/24 is the management network address space at the NOC.

IOS

interface Serial0/0
description to_OOBM_Backbone
ip address 10.1.20.3 255.255.255.0
ip access-group 100 in
ip access-group 101 out
interface Fastethernet 0/0
description Enclave_Management_LAN
ip address 10.1.1.2 255.255.255.0
interface Fastethernet 0/1
description to_our_ServiceNet
ip address 172.20.5.2 255.255.255.0
interface Fastethernet 0/2
description to_our_PrivateNet
ip address 172.20.4.2 255.255.255.0
!
access-list 100 permit ip 10.2.2.0 0.0.0.255 10.1.1.0 0.0.0.255
access-list 100 deny ip any any log

Fix Text (F-17734r2_fix)
Configure access control lists or filters to block any traffic from the management network destined for the managed network's production address spaces.