September 8, 2020—KB4577066 (Monthly Rollup)

Applies to: Windows 8.1Windows Server 2012 R2Windows Embedded 8.1 Industry Enterprise

Improvements and fixes


This security update includes improvements and fixes that were a part of update KB4571703 (released August 11, 2020) and addresses the following issues:

  • Updates time zone information for Yukon, Canada. For more information, see DST changes in Windows for Yukon, Canada: September 8, 2020.
  • Addresses an issue when you evaluate the compatibility status of the Windows ecosystem to help ensure application and device compatibility for all updates to Windows.
  • Addresses a security vulnerability issue with user proxies and HTTP-based intranet servers. After you install this update, HTTP-based intranet servers cannot leverage a user proxy to detect updates by default. Scans that use these servers will fail if the clients do not have a configured system proxy. If you must leverage a user proxy, you must configure the behavior by using the Windows Update policy “Allow user proxy to be used as a fallback if detection using system proxy fails.” This change does not affect customers who secure their Windows Server Update Services (WSUS) servers that use the Transport Layer Security (TLS) or Secure Sockets Layer (SSL) protocols. For more information, see Improving security for devices receiving updates via WSUS.
  • Security updates to Windows Media, Windows Input and Composition, Windows App Platform and Frameworks, Windows Graphics, Windows Cloud Infrastructure, Windows Authentication, Windows Cryptography, Windows Fundamentals, Windows Kernel, Windows Hybrid Cloud Networking, Windows Peripherals, Windows Storage and Filesystems, Windows Network Security and Containers, Windows Update Stack, the Microsoft Scripting Engine, and Windows SQL components.

For more information about the resolved security vulnerabilities, please refer to the Security Update Guide.

Known issues in this update


Symptom Workaround
Certain operations, such as rename, that you perform on files or folders that are on a Cluster Shared Volume (CSV) may fail with the error, “STATUS_BAD_IMPERSONATION_LEVEL (0xC00000A5)”. This occurs when you perform the operation on a CSV owner node from a process that doesn’t have administrator privilege.

Do one of the following:

  • Perform the operation from a process that has administrator privilege.
  • Perform the operation from a node that doesn’t have CSV ownership.

Microsoft is working on a resolution and will provide an update in an upcoming release.

How to get this update


Before installing this update

We strongly recommend that you install the latest servicing stack update (SSU) for your operating system before you install the latest Rollup. SSUs improve the reliability of the update process to mitigate potential issues while installing the Rollup and applying Microsoft security fixes. For general information about SSUs, see Servicing stack updates and Servicing Stack Updates (SSU): Frequently Asked Questions.

If you use Windows Update, the latest SSU (KB4566425) will be offered to you automatically. To get the standalone package for the latest SSU, search for it in the Microsoft Update Catalog

Install this update

Release Channel Available Next Step
Windows Update and Microsoft Update Yes None. This update will be downloaded and installed automatically from Windows Update.
Microsoft Update Catalog Yes To get the standalone package for this update, go to the Microsoft Update Catalog website.
Windows Server Update Services (WSUS) Yes

This update will automatically sync with WSUS if you configure Products and Classifications as follows:

Product: Windows 8.1, Windows Server 2012 R2, Windows Embedded 8.1 Industry Enterprise, Windows Embedded 8.1 Industry Pro

Classification: Security Updates

 

File information

For a list of the files that are provided in this update, download the file information for update 4577066