Description of the Security Only update for the .NET Framework 3.5.1 for Windows 7 SP1 and Windows Server 2008 R2 SP1: September 12, 2017

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Summary

This security update resolves a vulnerability in the Microsoft .NET Framework that could allow remote code execution when Microsoft .NET Framework processes untrusted input. An attacker who successfully exploits this vulnerability in software by using the .NET Framework could take control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts that have full user rights. Users whose accounts are configured to have fewer user rights on the system could be less affected than users who operate by using administrative user rights.To exploit the vulnerability, an attacker must first convince the user to open a malicious document or application.This security update addresses the vulnerability by correcting how the .NET Framework validates untrusted input. To learn more about this vulnerability, see Microsoft Common Vulnerabilities and Exposures CVE-2017-8759.Important

• 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 7 Service Pack 1 (SP1) and Windows Server 2008 R2 SP1, see the following article in the Microsoft Knowledge Base:4041090 Security Only update for the .NET Framework 3.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, and 4.7 updates for Windows 7 SP1 and Windows Server 2008 R2 SP1 and for the .NET Framework 4.6 for Windows Server 2008 SP2: September 12, 2017

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:

1. Click Start, clickAdministrative Tools, and then clickMicrosoft Windows Server Update Services 3.0.
2. Expand ComputerName, and then clickAction.
3. Click Import Updates.
4. WSUS opens a browser window in which you may be prompted to install an ActiveX control. You must install the ActiveX control to continue.
5. After the control is installed, you see the Microsoft Update Catalog screen. Enter4041090into theSearchbox, and then clickSearch.
6. Locate the .NET Framework packages that match the operating systems, languages, and processors in your environment. Click Add to add them to your basket.
7. After you select all the packages that you need, click View Basket.
8. Click Import to import the packages to your WSUS server.
9. To return to WSUS, click Close after the packages are imported.
   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:20170912 Security update deployment information: September 12, 2017

Update removal information

Note We do not recommend that you remove any security update. To remove this update, use thePrograms 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 replaces update 2978120.

File information

File hash

Package Name	Package Hash SHA 1	Package Hash SHA 2
Windows6.1-KB4040966-ia64.msu	FFFD298DA2ED458AF62D59ABB08717D3FD32060D	3B3967615B298883DC6FFF5D866B58609A69B8C65744925C9A2C9664080A9E42
Windows6.1-KB4040966-x64.msu	E7962089CE768C11B0AAFC644ABB7DF0E985BDEA	00B3FBE60AAD3B57BBFFB0409CE8EEF83B3FACC570AF3875ED92D5353EBDD8F3
Windows6.1-KB4040966-x86.msu	B87D0590D06F1EEF94F71EABB8F64005AD2F81C6	253E3EC86079F1F683E6549F650E790C424A76B15EE7D4CB0508B5048091737E

File attributes

The English (United States) version of this hotfix installs files that have the attributes that are listed in the following tables. The dates and the times for these files are listed in Coordinated Universal Time (UTC). The dates and the 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 the times may change when you perform certain operations on the files.For all x86-based systemsFile name	File version	File size	Date	Time
system.runtime.remoting.dll	2.0.50727.8771	307,200	31-Aug-2017	13:04
For all x64-based systemsFile name	File version	File size	Date	Time
—	—	—	—	—
system.runtime.remoting.dll	2.0.50727.8771	307,200	31-Aug-2017	13:04
system.runtime.remoting.dll	2.0.50727.8771	307,200	31-Aug-2017	13:04
For all IA64-based systemsFile name	File version	File size	Date	Time
—	—	—	—	—
system.runtime.remoting.dll	2.0.50727.8771	307,200	31-Aug-2017	13:04
system.runtime.remoting.dll	2.0.50727.8771	307,200	31-Aug-2017	13:04

How to obtain help and support for this security update

• Help for installing updates: Windows Update FAQ
• Security solutions for IT professionals: TechNet Security Support and Troubleshooting
• Help for protecting your Windows-based products and services from viruses and malware: Microsoft Secure
• Local support according to your country: International Support

Applies to

This article applies to the following:

• Microsoft .NET Framework 3.5.1 when used with:
  • Windows Server 2008 R2 Service Pack 1
  • Windows 7 Service Pack 1