Check: WDNS-CM-000017
Microsoft Windows 2012 Server Domain Name System STIG:
WDNS-CM-000017
(in versions v2 r6 through v2 r4)
Title
In a split DNS configuration, where separate name servers are used between the external and internal networks, the external name server must be configured to not be reachable from inside resolvers. (Cat II impact)
Discussion
Instead of having the same set of authoritative name servers serve different types of clients, an enterprise could have two different sets of authoritative name servers. One set, called external name servers, can be located within a DMZ; these would be the only name servers that are accessible to external clients and would serve RRs pertaining to hosts with public services (web servers that serve external web pages or provide B2C services, mail servers, etc.). The other set, called internal name servers, is to be located within the firewall and should be configured so they are not reachable from outside and hence provide naming services exclusively to internal clients.
Check Content
Consult with the System Administrator to review the external Windows DNS Server's Endpoint Security Solution (ESS) firewall policy. The inbound TCP and UDP ports 53 rule should be configured to only restrict IP addresses from the internal network. If the ESS firewall policy is not configured with the restriction, consult with the network firewall administrator to confirm the restriction on the network firewall. If neither the DNS server's ESS firewall policy nor the network firewall is configured to block internal hosts from querying the external DNS server, this is a finding.
Fix Text
Configure the external DNS server's firewall policy, or the network firewall, to block queries from internal hosts.
Additional Identifiers
Rule ID: SV-215586r879887_rule
Vulnerability ID: V-215586
Group Title: SRG-APP-000516-DNS-000092
Expert Comments
CCIs
Number | Definition |
---|---|
CCI-000366 |
The organization implements the security configuration settings. |
Controls
Number | Title |
---|---|
CM-6 |
Configuration Settings |