January 12, 2021—KB4598278 (Monthly Rollup)


None **IMPORTANT** Adobe Flash Player went out of support on December 31, 2020. For more information, see [Adobe Flash end of support on December 31, 2020](<https://docs.microsoft.com/en-us/lifecycle/announcements/adobe-flash-end-of-support#:~:text=Adobe%20will%20end%20support%20of,site%2Dby%2Dsite%20basis.>). Flash content will be blocked from running in Flash Player beginning January 12, 2021. For more information, see [Adobe Flash Player EOL General Information Page](<https://www.adobe.com/products/flashplayer/end-of-life.html>). **IMPORTANT** Windows Server 2012 has reached the end of mainstream support and is now in extended support. Starting in July 2020, there will no longer be optional releases (known as "C" or "D" releases) for this operating system. Operating systems in extended support have only cumulative monthly security updates (known as the "B" or Update Tuesday release). For information about the various types of Windows updates, such as critical, security, driver, service packs, and so on, please see the following [article](<https://support.microsoft.com/help/824684>). To view other notes and messages, see the Windows Server 2012 update history [home page](<https://support.microsoft.com/help/4009471>). ## Improvements and fixes This security update includes improvements and fixes that were a part of update [KB4592468](<https://support.microsoft.com/help/4592468>) (released previous December 8, 2020) and addresses the following issues: * Addresses a security bypass vulnerability that exists in the way the Printer Remote Procedure Call (RPC) binding handles authentication for the remote Winspool interface. For more information, see [KB4599464](<https://support.microsoft.com/help/4599464>). * Addresses a security vulnerability issue with HTTPS-based intranet servers. After you install this update, HTTPS-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**. To make sure that the highest levels of security, additionally leverage Windows Server Update Services (WSUS) Transport Layer Security (TLS) certificate pinning on all devices. For more information, see [Changes to scans, improved security for Windows devices](<https://aka.ms/WSUS-scans-part2>). **Note** This change does not affect customers who use HTTP WSUS servers. * Addresses an issue in which a principal in a trusted Managed Identity for Application (MIT) realm does not obtain a Kerberos Service ticket from Active Directory domain controllers (DCs). This issue occurs after Windows Updates that contains [CVE-2020-17049](<https://msrc.microsoft.com/update-guide/vulnerability/CVE-2020-17049>) protections released between November 10 and December 8, 2020 are installed and **PerfromTicketSignature** is configured to **1** or higher. Ticket acquisition fails with **KRB_GENERIC_ERROR** if callers submit a PAC-less Ticket Granting Ticket (TGT) as an evidence ticket without providing the **USER_NO_AUTH_DATA_REQUIRED** flag. * Security updates to Windows App Platform and Frameworks, Windows Graphics, Windows Media, Windows Fundamentals, Windows Cryptography, Windows Virtualization, and Windows Hybrid Storage Services. For more information about the resolved security vulnerabilities, please refer to the new [Security Update Guide](<https://msrc.microsoft.com/update-guide>) website. ## 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 installing 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](<https://docs.microsoft.com/en-us/windows/deployment/update/servicing-stack-updates>) and [Servicing Stack Updates (SSU): Frequently Asked Questions](<https://support.microsoft.com/help/4535697>).If you use Windows Update, the latest SSU ([KB4566426](<https://support.microsoft.com/help/4566426>)) will be offered to you automatically. To get the standalone package for the latest SSU, search for it in the [Microsoft Update Catalog](<http://www.catalog.update.microsoft.com/home.aspx>). **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](<https://www.catalog.update.microsoft.com/Search.aspx?q=KB4598278>) website. Windows Server Update Services (WSUS)| Yes| This update will automatically sync with WSUS if you configure **Products and Classifications** as follows:**Product**: Windows Server 2012, Windows Embedded 8 Standard**Classification**: Security Updates **File information**For a list of the files that are provided in this update, download the [file information for update 4598278](<https://download.microsoft.com/download/2/c/c/2cc78328-eccd-4783-9752-db07d15856f6/4598278.csv>).