Security Update for Windows 10 21H1 – KB5008212

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December month’s Security Update for Windows 10 version 21H1 has been released by Microsoft on 14th December. The update resolves 30 security vulnerabilities, besides improving the quality of the operating system. Security update KB5008212 is customized to help secure Windows 10 version 21H1. Below, we look at the various factors, features, and details of the security update KB5008212 for Windows 10 version 21H1.

How can I get the KB5008212 update for Windows 10 version 21H1?

Microsoft offers multiple options to update Windows 10 21H1 to the latest security update KB5008212. The security update weighs around 650 MB in size. This update will upgrade the build on your computer to 19043.1415. 19043 is the build that brought in the 21H1 version to the Windows 10 operating system on your computer.

KB5008212 security update for Windows 10 version 21H1 has been made available in the following ways by Microsoft:

  • KB5008212 can be downloaded manually, as a msu image, from the Microsoft Update Catalog. The size of the update file is close to 650 MB. You can download the security update KB5008212 for Windows 10 21H1 from this page – https://www.catalog.update.microsoft.com/Search.aspx?q=KB5008212. Since Windows 10 have a lot of versions on the page, do make sure that you are downloading the relevant security update for Windows 10 21H1 version.
  • KB5008212 security update on Windows 10 is also available for automatic patching through the Windows Update settings on your computer.
  • KB5008212 can also be downloaded using Windows Update for Business for the Pro version of the operating system.
  • Finally, Windows Server Update Service (WSUS) can automatically synchronize the Windows 10 on your computer to the updated version if you have configured the product as Windows 10 and classified the security updates.

Depending on your preferred approach to updating Windows 10 21H1 with security update KB5008212, you may take a manual approach or choose an automatic update with the security update.

What improvements or bug fixes have been made in KB5008212 for Windows 10 version 21H1?

KB5008212 security update builds upon the Windows 10 version 2004 and brings in all the core features of version 2004 to Windows 10 version 21H1.

Vulnerabilities resolved in KB5008212 for Windows 10 21H1

In all, 30 vulnerabilities have been resolved as part of the security update KB5008212 for Windows 10 21H1. We discuss all these vulnerabilities below so that you could see the affected services or components on Windows 10 21H1.

Critical vulnerabilities resolved in KB5008212 for Windows 21H1

3 vulnerabilities of a critical nature have been resolved in the KB5008212 security update for Windows 10 version 21H1. All these vulnerabilities are of the type of remote code execution. Remote code execution vulnerabilities are very dangerous. A remote attacker could deploy and execute malicious code on the affected computer. The three critical vulnerabilities that have found a solution in the security update KB5008212 are as follows:

  • CVE-2021-43215 – this is a remote code execution vulnerability with a CVSS score of 9.8. It requires immediate patching. An attacker could send a specially crafted request to the Internet Storage Name Service (iSNS) server, which could result in remote code execution.
  • CVE-2021-43217 – this is a remote code execution vulnerability with a CVSS score of 8.1. It requires immediate patching. An attacker could cause a buffer overflow write leading to unauthenticated non-sandboxed code execution. This vulnerability affects the Windows Encrypting File System (EFS).
  • CVE-2021-43233 – this is a remote code execution vulnerability that has a CVSS score of 7.5. It affects the Remote Desktop Client software. The vulnerability requires immediate patching.

All these vulnerabilities cause a significant challenge for the system administrators. Since the security update, KB5008212 needs a reboot, a planned maintenance window is the right way to go about updating Windows 10 21H1 on your network.

KB5008212 remote code execution vulnerabilities with important severity for Windows 10 version 21H1

In addition to the 3 critical vulnerabilities of the type remote code execution, there are two additional remote code execution vulnerabilities that have an important severity level for the Windows 10 version 21H1. The two important severity vulnerabilities that have been resolved as part of the KB5008212 security update for Windows 10 version 21H1 are given below.

  • CVE-2021-43232 – carries a CVSS score of 7.8 and affects the Windows Event Tracing Service.
  • CVE-2021-43234 – carries a CVSS score of 7.8 and affects Windows Fax Service.

Both vulnerabilities carry a high CVSS score of 7.8, thus needing your attention on a priority basis for immediate patching.

Elevation of Privileges vulnerabilities resolved in KB5008212 for Windows 10 version 21H1

There are fifteen security vulnerabilities that could cause the elevation of privileges on a compromised Windows 10 21H1. Elevation of privileges can lead to an attacker assuming elevated authentication credentials. With elevated credentials, an attacker can perform malicious actions on the target computers. The 15 elevation of privilege vulnerabilities that can be resolved as part of the security update KB5008212 for Windows 10 version 21H1 is mentioned below.

  • CVE-2021-43893 – CVSS score of 7.5 and affects Windows Encrypting File System (EFS)
  • CVE-2021-43883 – CVSS score of 7.8 and affects Windows Installer
  • CVE-2021-43248 – CVSS score of 7.8 and affects Windows Digital Media Receiver
  • CVE-2021-43247 – CVSS score of 7.8 and affects Windows TCP/IP driver.
  • CVE-2021-43240 – CVSS score of 7.8 and affects Windows NTFS Set Short Name.
  • CVE-2021-43239 – CVSS score of 7.1 and affects Windows Recovery Environment Agent.
  • CVE-2021-43238 – CVSS score of 7.8 and affects Windows Remote Access.
  • CVE-2021-43237 – CVSS score of 7.8 and affect Windows Setup.
  • CVE-2021-43231 – CVSS score of 7.8 and affects Windows NTFS.
  • CVE-2021-43230 – CVSS score of 7.8 and affects Windows NTFS.
  • CVE-2021-43229 – CVSS score of 7.8 and affects Windows NTFS.
  • CVE-2021-43226 – CVSS score of 7.8 and affects Windows Common Log File System Driver.
  • CVE-2021-43223 – CVSS score of 7.8 and affects Windows Remote Access Connection Manager.
  • CVE-2021-41333 – CVSS score of 7.8 and affects Windows Print Spooler.
  • CVE-2021-43207 – CVSS score of 7.8 and affects Windows Common Log File System Driver.

Most elevation of privilege vulnerabilities on Windows 10 21H1 carry high CVSS scores and pose significant risks to the Windows 10 21H1 based infrastructure.

Information Disclosure vulnerabilities resolved in KB5008212 on Windows 10 21H1

Information disclosure vulnerabilities can lead to loss of personal or business data from the affected system. Windows 10 version 21H1 has 7 information disclosure vulnerabilities that have been patched in the security update KB5008212 for Windows 10 21H1. The information disclosure vulnerabilities that have been patched in the security update KB5008212 for Windows 10 21H1 are given below.

  • CVE-2021-43244 – CVSS score of 6.5 and affects Windows Kernel.
  • CVE-2021-43236 – CVSS score of 7.5 and affects Microsoft Messaging Queue
  • CVE-2021-43235 – CVSS score of 5.5 and affects the ‘Storage Spaces Controller’.
  • CVE-2021-43227 – CVSS score of 5.5 and affects the ‘Storage Spaces Controller’.
  • CVE-2021-43224 – CVSS score of 5.5 and affects the Windows Common Log File System Driver.
  • CVE-2021-43222 – CVSS score of 7.5 and affects Microsoft Messaging Queue.
  • CVE-2021-43216 – CVE-2021-43216 – CVSS score of 6.5 and affects Microsoft Local Security Authority Server (lsasrv).

Denial of Service vulnerabilities resolved in KB5008212 for Windows 10 21H1

There are three denial of service vulnerabilities that have been resolved as part of the security update KB5008212 for Windows 10 version 21H1. Denial of service vulnerability can cause service disruptions through compromised computer systems. The 3 denial of service vulnerabilities that have been resolved are mentioned below.

  • CVE-2021-43246 – carries a CVSS score of 5.6 and affects Windows Hyper V service.
  • CVE-2021-43228 – carries a CVSS score of 7.5 and affects SymCrypt.
  • CVE-2021-43219 – carries a CVSS score of 7.4 and affects DirectX Graphics Kernel File.

All these Windows 10 21H1 vulnerabilities would get patched with the KB5008212 security update. Critical vulnerabilities require immediate action, and it would be suggested that you may plan for a maintenance schedule to patch the Windows 10 computer systems.

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Rajesh Dhawan

Rajesh Dhawan is a technology professional who loves to blog about smart wearables, Cloud computing and Microsoft technologies. He loves to break complex problems into manageable chunks of meaningful information.