KLA11783
Microsoft Advisory for Windows DNS servers

Microsoft is aware of a vulnerability involving packet amplification that affects Windows DNS servers.

An attacker who successfully exploited this vulnerability could cause the DNS Server service to become nonresponsive.

To exploit this vulnerability an attacker would need to have access to at least one client and a domain that replies with a large volume of referral records, without glue records, that point to external victim sub domains. While resolving a name from the attacker client, for each referral record found, the resolver contacts the victim domain. This action can generate a large number of communications between the recursive resolver and the victim’s authoritative DNS server to cause a Distributed Denial of Service (DDoS) attack.

Microsoft Windows Server

Install necessary updates from the KB section, that are listed in your Windows Update (Windows Update usually can be accessed from the Control Panel)