The Windows DNS Server authoritative for local zones must only point root hints to the DNS servers that host the internal root domain.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-259357	WDNS-22-000027	SV-259357r945263_rule		Medium

Description
All caching name servers must be authoritative for the root zone because, without this starting point, they would have no knowledge of the DNS infrastructure and thus would be unable to respond to any queries. The security risk is that an adversary could change the root hints and direct the caching name server to a bogus root server. At that point, every query response from that name server is suspect, which would give the adversary substantial control over the network communication of the name servers' clients. When authoritative servers are sent queries for zones that they are not authoritative for, and they are configured as a noncaching server (as recommended), they can be configured to either return a referral to the root servers or refuse to answer the query. The recommendation is to configure authoritative servers to refuse to answer queries for any zones for which they are not authoritative. This is more efficient for the server and allows it to spend more of its resources fulfilling its intended purpose of answering authoritatively for its zone.

Description

All caching name servers must be authoritative for the root zone because, without this starting point, they would have no knowledge of the DNS infrastructure and thus would be unable to respond to any queries. The security risk is that an adversary could change the root hints and direct the caching name server to a bogus root server. At that point, every query response from that name server is suspect, which would give the adversary substantial control over the network communication of the name servers' clients. When authoritative servers are sent queries for zones that they are not authoritative for, and they are configured as a noncaching server (as recommended), they can be configured to either return a referral to the root servers or refuse to answer the query. The recommendation is to configure authoritative servers to refuse to answer queries for any zones for which they are not authoritative. This is more efficient for the server and allows it to spend more of its resources fulfilling its intended purpose of answering authoritatively for its zone.

STIG	Date
Microsoft Windows Server Domain Name System (DNS) Security Technical Implementation Guide	2024-01-09

Details

Check Text ( C-63096r939774_chk )
Note: If the Windows DNS Server is in the classified network, this check is not applicable. Log on to the authoritative DNS server using the Domain Admin or Enterprise Admin account. Press the Windows key + R and execute "dnsmgmt.msc". Right-click the DNS server and select "Properties". Select the "Root Hints" tab. Verify "Root Hints" is empty or only has entries for internal zones under "Name servers:". All internet root server entries must be removed. If "Root Hints" is not empty or entries on the "Root Hints" tab under "Name servers:" are external to the local network, this is a finding.

Check Text ( C-63096r939774_chk )

Note: If the Windows DNS Server is in the classified network, this check is not applicable.

Log on to the authoritative DNS server using the Domain Admin or Enterprise Admin account.

Press the Windows key + R and execute "dnsmgmt.msc".

Right-click the DNS server and select "Properties".

Select the "Root Hints" tab.

Verify "Root Hints" is empty or only has entries for internal zones under "Name servers:". All internet root server entries must be removed.

If "Root Hints" is not empty or entries on the "Root Hints" tab under "Name servers:" are external to the local network, this is a finding.

Fix Text (F-63004r939775_fix)
Log on to the authoritative DNS server using the Domain Admin or Enterprise Admin account. Press the Windows key + R and execute "dnsmgmt.msc". Right-click the DNS server and select "Properties". Select the "Root Hints" tab. Remove the root hints from the DNS Manager, the CACHE.DNS file, and from Active Directory for name servers outside the internal network. Replace the existing root hints with new root hints of internal servers. If the DNS server is forwarding, click to select the "Do not use recursion for this domain"" check box on the "Forwarders" tab in DNS Manager to ensure the root hints will not be used.

Fix Text (F-63004r939775_fix)

Log on to the authoritative DNS server using the Domain Admin or Enterprise Admin account.

Press the Windows key + R and execute "dnsmgmt.msc".

Right-click the DNS server and select "Properties".

Select the "Root Hints" tab.

Remove the root hints from the DNS Manager, the CACHE.DNS file, and from Active Directory for name servers outside the internal network.

Replace the existing root hints with new root hints of internal servers.

If the DNS server is forwarding, click to select the "Do not use recursion for this domain"" check box on the "Forwarders" tab in DNS Manager to ensure the root hints will not be used.