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V-285280

CAT II (Medium)

For zones split between the external and internal sides of a network, the resource records (RRs) for the external hosts must be separate from the RRs for the internal hosts.

Rule ID

SV-285280r1258968_rule

STIG

Infoblox NIOS 9.x Security Technical Implementation Guide

Version

V1R1

CCIs

CCI-000366

Discussion

Authoritative name servers for an enterprise may be configured to receive requests from both external and internal clients. External clients must receive RRs that pertain only to public services (public web server, mail server, etc.). Internal clients must receive RRs pertaining to public services as well as internal hosts. The zone information that serves the RRs on both the inside and the outside of a firewall should be split into different physical files for these two types of clients (one file for external clients and one file for internal clients).

Check Content

Verify Infoblox is configured to use DNS View match clients in environments with Internal and External DNS Views.

DNS Views allow a single zone to have two different data sets, with the response based on a client match list. 

1. When DNS Views are used, the top-level configuration of Data Management >> DNS >> Zones tab will display available views. 
2. Select the desired view using the checkbox and click "Edit". 
3. Select the "Match Clients" tab.
4. Verify the "Match Clients" configuration properly separates the internal and external DNS views.
 
If DNS Views are not used, and the client match ACL and/or match destination ACL is not validated, this is a finding.

To minimize erroneous response/data spillage/complexity, each appliance should only host one DNS view. If there are multiple DNS views (on a single appliance), then it is required that a combination of match clients and/or match destination ACLs are implemented ("additive inverse" logic, so that only ONE DNS view can match for all possible combinations).

Fix Text

1. Navigate to Data Management >> DNS >> Zones tab and review each zone. 
2. Remove any RRs listed in the internal DNS service member configuration (DNS view) that resolve for external hosts.
3. Remove any RRs listed in the external DNS service member configuration (DNS view) that resolve to internal hosts.
4. For hosts intended to be accessed by both internal and external clients, configure unique IP addresses in each of the internal and external DNS service members, respective to their location. 
5. The perimeter firewall, or other routing device, must be configured to perform Network Address Translation to the true IP address of the destination.

To minimize erroneous response/data spillage/complexity, each appliance should only host one DNS view. If there are multiple DNS views on a single appliance, then it is required that a combination of match clients and/or match destination ACLs are implemented ("additive inverse" logic, so that only ONE DNS view can match for all possible combinations).