Applies to:

Microsoft .NET Framework 3.5.1

IMPORTANT Verify that you have installed the required updates listed in the How to get this update section before installing this update. 

IMPORTANT Some customers who use Windows Server 2008 R2 SP1 and have activated their ESU multiple activation key (MAK) add-on before installing the January 14, 2020 updates might need to re-activate their key. Re-activation on the affected devices should only be required once.  For information on activation, see this blog post.

IMPORTANT WSUS scan cab files will continue to be available for Windows 7 SP1 and Windows Server 2008 R2 SP1. If you have a subset of devices running these operating systems without ESU, they might show as non-compliant in your patch management and compliance toolsets.

IMPORTANT Customers who have purchased the Extended Security Update (ESU) for on-premises versions of these operating systems must follow the procedures in KB4522133 to continue receiving security updates after extended support ends on January 14, 2020. For more information on ESU and which editions are supported, see KB4497181.

IMPORTANT Starting on January 15, 2020, a full-screen notification will appear that describes the risk of continuing to use Windows 7 Service Pack 1 after it reaches end of support on January 14, 2020. The notification will remain on the screen until you interact with it. This notification will only appear on the following editions of Windows 7 Service Pack 1:

Note The notification will not appear on domain-joined machines or machines in kiosk mode.

Summary

Security improvements

An elevation of privilege vulnerability exists when ASP.NET or .NET Framework web applications running on IIS improperly allow access to cached files. An attacker who successfully exploited this vulnerability could gain access to restricted files. To exploit this vulnerability, an attacker would need to send a specially crafted request to an affected server. The update addresses the vulnerability by changing how ASP.NET and .NET Framework handle requests.

To learn more about the vulnerabilities, go to the following Common Vulnerabilities and Exposures (CVE).

A remote code execution vulnerability exists when Microsoft .NET Framework processes input. An attacker who successfully exploited this vulnerability could take control of an affected system. To exploit the vulnerability, an attacker would need to be able to upload a specially crafted file to a web application. The security update addresses the vulnerability by correcting how .NET Framework processes input.

For more information go to: https://go.microsoft.com/fwlink/?linkid=2138023

To learn more about the vulnerabilities, go to the following Common Vulnerabilities and Exposures (CVE).

Additional information about this update

The following articles contain additional information about this update as it relates to individual product versions.

  • 4570500 Description of the Security Only Update for .NET Framework 3.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8 for Windows 7 SP1 and Windows Server 2008 R2 SP1 (KB4570500)

How to obtain and install the update

Before installing this update

Prerequisite:

To apply this update, you must have .NET Framework 3.5.1 installed.

You must install the updates listed below and restart your device before installing the latest Rollup. Installing these updates improves the reliability of the update process and mitigates potential issues while installing the Rollup and applying Microsoft security fixes.

  1. The March 12, 2019 servicing stack update (SSU) (KB4490628). To get the standalone package for this SSU, search for it in the Microsoft Update Catalog. This update is required to install updates that are only SHA-2 signed.

  2. The latest SHA-2 update (KB4474419) released September 10, 2019. If you are using Windows Update, the latest SHA-2 update will be offered to you automatically. This update is required to install updates that are only SHA-2 signed. For more information on SHA-2 updates, see 2019 SHA-2 Code Signing Support requirement for Windows and WSUS.

  3. The Extended Security Updates (ESU) Licensing Preparation Package (KB4538483) released February 11, 2020. The ESU licensing preparation package will be offered to you from WSUS. To get the standalone package for ESU licensing preparation package, search for it in the Microsoft Update Catalog.

Install this update

Release Channel

Available

Next Step

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 7 Service Pack 1, Windows Server 2008 R2 Service Pack 1,Windows Embedded Standard 7 Service Pack 1, Windows Embedded POSReady 7

Classification: Security Updates

Restart requirement

You must restart the computer after you apply this update if any affected files are being used. We recommend that you exit all .NET Framework-based applications before you apply this update.

Update deployment information

For deployment details for this security update, go to the following article in the Microsoft Knowledge Base:

20200811 Security update deployment information: August 11, 2020

Update removal information

Note We do not recommend that you remove any security update. To remove this update, use the Programs and Features item in Control Panel.

Update restart information

This update does not require a system restart after you apply it unless files that are being updated are locked or are being used.


File information
The English (United States) version of this software update installs files that have the attributes that are listed in the following tables.

Windows 7 and Windows Server 2008 R2 file information

Note: The MANIFEST files (.manifest) and MUM files (.mum) that are installed are not listed.

File information

File hash information

File name

SHA1 hash

SHA256 hash

Windows6.1-KB4569736-x64.msu

0BD4A25D7E6DCB744D6D0D98DA096564079A3DC8

EDA8D3ABBAD3325349FC27C54C9F6488E402F949D62F71CD8D21AFDE61661645

Windows6.1-KB4569736-x86.msu

CFE06928D60254EE4045DDBD0A90DF95C72D90B6

64097A53527B2303BA4353F6299E5FDDA62A55DB517E2DA761C0634F69FBCFB3

For all supported x64-based versions

File name

File version

File size

Date

Time

Platform

SP requirement

Service branch

Aspnet_wp.exe

2.0.50727.8951

45,456

16-Jul-2020

00:28

x64

SPN

AMD64_NETFX-ASP

System.web.regularexpressions.dll

2.0.50727.8951

98,304

16-Jul-2020

00:28

x86

None

Not applicable

Webengine.dll

2.0.50727.8951

748,936

16-Jul-2020

00:28

x64

None

Not applicable

System.web.dll

2.0.50727.8951

5,300,224

16-Jul-2020

00:28

x64

None

Not applicable

System.web.regularexpressions.dll

2.0.50727.8951

98,304

16-Jul-2020

00:29

x86

None

Not applicable

Aspnet_wp.exe

2.0.50727.8951

33,680

16-Jul-2020

00:29

x86

SPN

X86_NETFX-ASP

Webengine.dll

2.0.50727.8951

439,680

16-Jul-2020

00:29

x86

None

Not applicable

System.web.dll

2.0.50727.8951

5,292,032

16-Jul-2020

00:29

x86

None

Not applicable

For all supported x86-based versions

File name

File version

File size

Date

Time

Platform

SP requirement

Service branch

System.web.regularexpressions.dll

2.0.50727.8951

98,304

16-Jul-2020

00:29

x86

None

Not applicable

Aspnet_wp.exe

2.0.50727.8951

33,680

16-Jul-2020

00:29

x86

SPN

X86_NETFX-ASP

Webengine.dll

2.0.50727.8951

439,680

16-Jul-2020

00:29

x86

None

Not applicable

System.web.dll

2.0.50727.8951

5,292,032

16-Jul-2020

00:29

x86

None

Not applicable

Information about protection and security

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