Applies to:

Microsoft .NET Framework 3.5

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).

Important

  • As a reminder to advanced IT administrators, updates to .NET Framework 3.5 for Windows 8.1 and Windows Server 2012 R2 should only be applied on systems where .NET Framework 3.5 is present and enabled. Customers who attempt to pre-install updates to .NET Framework 3.5 to offline images that do not contain the .NET Framework 3.5 product enabled will expose these systems to failures to enable .NET Framework 3.5 after the systems are online. For more extensive information about deploying .NET Framework 3.5, see Microsoft .NET Framework 3.5 Deployment Considerations.

  • All updates for Windows 8.1, Windows RT 8.1, and Windows Server 2012 R2 require that update KB 2919355 is installed. We recommend that you install update KB 2919355 on your Windows 8.1-based, Windows RT 8.1-based, or Windows Server 2012 R2-based computer so that you receive updates in the future.

  • If you install a language pack after you install this update, you must reinstall this update. Therefore, we recommend that you install any language packs that you need before you install this update. For more information, see Add language packs to Windows.

Additional information about this update

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

  • 4570502 Description of the Security Only Update for .NET Framework 3.5, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8 for Windows 8.1 and Windows Server 2012 R2 (KB4570502)

How to obtain and install the update

Before installing this update

Prerequisite:

To apply this update, you must have .NET Framework 3.5 installed.

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 8.1 and Windows Server 2012 R2

Classification: Security Updates

Prerequisites

To apply this update, you must have .NET Framework 3.5 installed.

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 8.1 and Windows Server 2012 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

Windows8.1-KB4569737-x64.msu

0A1B0C231EB6AC1AB221054CA441E04FC6C4C34C

51A53CDF7272EFFB516239EF1CA4E0842D0814D7F19A2913442FE6BA3BDEC528

Windows8.1-KB4569737-x86.msu

C2BBDC7B2CF983429A2D2A8A5E7850F0D8794A24

85976AB4E1773516CAEF163D330349DDD9ADBC497089881A7765C4A08101CEBE

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

01-Jul-2020

13:22

x64

SPN

AMD64_NETFX-ASP

System.web.regularexpressions.dll

2.0.50727.8951

98,304

01-Jul-2020

13:22

x86

None

Not applicable

Webengine.dll

2.0.50727.8951

748,936

01-Jul-2020

13:22

x64

None

Not applicable

System.web.dll

2.0.50727.8951

5,300,224

01-Jul-2020

13:22

x64

None

Not applicable

System.web.regularexpressions.dll

2.0.50727.8951

98,304

01-Jul-2020

13:18

x86

None

Not applicable

Aspnet_wp.exe

2.0.50727.8951

33,680

01-Jul-2020

13:18

x86

SPN

X86_NETFX-ASP

Webengine.dll

2.0.50727.8951

439,680

01-Jul-2020

13:18

x86

None

Not applicable

System.web.dll

2.0.50727.8951

5,292,032

01-Jul-2020

13:18

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

01-Jul-2020

13:18

x86

None

Not applicable

Aspnet_wp.exe

2.0.50727.8951

33,680

01-Jul-2020

13:18

x86

SPN

X86_NETFX-ASP

Webengine.dll

2.0.50727.8951

439,680

01-Jul-2020

13:18

x86

None

Not applicable

System.web.dll

2.0.50727.8951

5,292,032

01-Jul-2020

13:18

x86

None

Not applicable

Information about protection and security

Need more help?

Expand your skills
Explore Training
Get new features first
Join Microsoft Insiders

Was this information helpful?

What affected your experience?

Thank you for your feedback!

×