This move will block vulnerable connections from noncompliant devices, according to a Microsoft Security and Response Center blog post. DC enforcement mode requires both Windows and non-Windows devices to use secure Remote Procedure Call (RPC) with a Netlogon secure channel, unless a business has allowed an account to be exposed by adding an exception for a noncompliant device.
CVE-2020-1472 is a privilege escalation flaw in the Windows Netlogon Remote Protocol (MS-NRPC) with a CVSS score of 10. It could enable an unauthenticated attacker to use MS-NRPC to connect to a domain controller and gain full admin access.
Since it was fixed in August, the Zerologon bug has been seen in active campaigns from Iranian threat group Mercury. The DHS s Cybersecurity and Infrastructure Security Agency (CISA) later issued an emergency directive for the flaw, requiring federal agencies to patch immediately.