Microsoft has outlined the steps its customers need to take to ensure that their devices are protected from ongoing attacks using exploits of Windows Server Zerologon (CVE-2020-1472).
The company updated its publication when its customers found it quite difficult and unsure if the update was enough to protect vulnerable Windows Server devices from attack.
In a step-by-step approach, the updated publication explains the exact steps administrators should take to make sure their machines are protected in the event of an incoming attacks designed to exploit Zerologon.
Microsoft outlines the following plan for Windows administrators to follow when implementing “CVE-2020-1472 | The security update of Netlogon Elevation of Privilege Vulnerability released as part of it Patch Tuesday in August 2020:
- UPDATED your Domain Controllers with an update released August 11, 2020 or later.
- FIND which devices are making vulnerable connections by monitoring event logs.
- ADDRESS non-compliant devices making vulnerable connections.
- ENABLE enforcement mode to address CVE-2020-1472 in your environment.
The Zerologon vulnerability
CVE-2020-1472 is a critical security vulnerability with a score of 10/10. It was named Zerologon by the security company Secura and when exploited, it allows intruders to increase privileges in an administrator domain.
This makes it very easy for them to take control of the domain, as they can change each user's password and run whatever command they want.
The security update released by Microsoft in August may cause authentication issues on some of the affected devices, and the company has released the Zerologon patch in two stages.
The first was released on August 11 as an update security version which will block its domain controllers serviceWindows Active Directory, to use insecure RPC communication.
It also records authentication requests from non-Windows devices that do not use secure RPC channels to give administrators time to correct errors.
As of February 9, 2021, as part of Patch updates Tuesday, η Microsoft θα κυκλοφορήσει μια άλλη ενημέρωση που θα επιτρέπει μια λειτουργία επιβολής που θα απαιτεί από όλες τις συσκευές δικτύου να χρησιμοποιούν safe RPC, unless expressly permitted by administrators.
We have updated the KB article for CVE-2020-1472 to provide clarity on customer actions to ensure they are protected. See details here: https://t.co/l4MwY9DFvt
- Security Response (@msftsecresponse) September 28, 2020
Ongoing Zerologon attacks
Last week, Microsoft warned administrators to urgently implement security updates for Zerologon after discovering that they are being used during attacks.
Microsoft Threat Intelligence analyst Kevin Beaumont confirmed that the attacks began on September 26, with attackers successfully exploiting a vulnerable honeypot on an Active Directory server using a Zerologon exploit.
Yesterday, security researchers at Cisco Talos also warned of "a sharp increase in vulnerability in Microsoft CVE-2020-1472".