Description of the Security Only update for .NET Framework 3.5 for Windows 8.1 and Server 2012 R2 (KB 4470602)

Summary

This security update resolves a vulnerability in Microsoft .NET Framework that could allow remote code execution when Microsoft .NET Framework doesn't validate input correctly. An attacker who successfully exploits this vulnerability could take control of an affected system. The attacker could then install programs; view, change, or delete data; or create new accounts that use full user rights. Users whose accounts are configured to have fewer user rights on the system could be less affected than users who operate with administrative user rights.

To exploit the vulnerability, an attacker would have to pass specific input to an application that uses susceptible .NET Framework methods.

This security update addresses the vulnerability by correcting how .NET Framework validates input.

To learn more about this vulnerability, see Microsoft Common Vulnerabilities and Exposures CVE-2018-8540.

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 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 security update

For more information about this security update as it relates to Windows 8.1, Windows RT 8.1, and Windows Server 2012 R2, see the following article in the Microsoft Knowledge Base:

4471983 Security Only updates for .NET Framework 3.5, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, and 4.7.2 for Windows 8.1 and Server 2012 R2 (KB 4471983)

How to obtain and install the update

Method 1: Microsoft Update Catalog

To get the stand-alone package for this update, go to the Microsoft Update Catalog.

Method 2: Windows Software Update Services (WSUS)

On your WSUS server, follow these steps:

Select Start, select Administrative Tools, and then select Microsoft Windows Server Update Services 3.0.
Expand ComputerName, and then select Action.
Select Import Updates.
WSUS opens a browser window in which you may be prompted to install an ActiveX control. Install the ActiveX control to continue.
After the ActiveX control is installed, you see the Microsoft Update Catalog screen. Type 4471983 in the Search box, and then select Search.
Locate the .NET Framework packages that match the operating systems, languages, and processors in your environment. Select Add to add them to your basket.
After you select all the packages that you need, select View Basket.
To import the packages to your WSUS server, select Import.
After the packages are imported, select Close to return to WSUS.

The updates are now available for installation through WSUS.

Update deployment information

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

20181211 Security update deployment information: December 11, 2018

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.

Update replacement information

This update does not replace any previously released update.

File information

File hash

File name	SHA1 hash	SHA256 hash
Windows8.1-KB4470602-x64.msu	654816AC517F5FF12686D4B5A5A16EFAE8AAC31F	B2C205183DB26AEE0AD63D38EF7336F76335A3FA0DA0D040E90C0903AD376143
Windows8.1-KB4470602-x86.msu	BAB64BD4A87DBFAE37C89CB6A0AD0BEE15268359	72D92CFA6B5D03D1FBB955D86FE4C7A155480B9731A17B5255D04F38FCD66B4E

File attributes for all supported x86-based systems

The English (United States) version of this update installs files that have the attributes that are listed in the following tables. The dates and times for these files are listed in Coordinated Universal Time (UTC). The dates and times for these files on your local computer are displayed in your local time together with your current daylight saving time (DST) bias. Additionally, the dates and times may change when you perform certain operations on the files.

File name	File version	File size	Date	Time
system.web.extensions.dll	3.5.30729.8814	1,282,048	02-Nov-2018	13:13
system.web.extensions.dll	3.5.30729.8814	1,282,048	02-Nov-2018	13:13

File attributes for all supported x64-based systems