Description of the Security Only update for .NET Framework 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 4338605)

This security update resolves the following vulnerabilities:

• A "remote code execution" vulnerability exists when .NET Framework does not validate input correctly. An attacker who successfully exploits this vulnerability 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 have administrative user rights. To exploit the vulnerability, an attacker would have to pass specific input to an application through 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-2018-8284.
• An "elevation of privilege" vulnerability exists in .NET Framework that could allow an attacker to elevate their user rights level. To exploit the vulnerability, an attacker would first have to access the local computer, and then run a malicious program. This update addresses the vulnerability by correcting how .NET Framework enables COM objects. To learn more about this vulnerability, see Microsoft Common Vulnerabilities and Exposures CVE-2018-8202.
• A "security feature bypass" vulnerability exists when .NET Framework components do not correctly validate certificates. An attacker could present expired certificates when challenged. This security update addresses the vulnerability by making sure that .NET Framework components correctly validate certificates. To learn more about this vulnerability, see Microsoft Common Vulnerabilities and Exposures CVE-2018-8356.

Important

• All updates for Windows 8.1 and Windows Server 2012 R2 require update 2919355 to be installed. We recommend that you install update 2919355 on your Windows RT 8.1-based, Windows 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.

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

4340006 Security Only update for .NET Framework 3.5 SP1, 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 4340006)

• After you install any of the July 2018 .NET Framework Security Updates, a COM component fails to load because of “access denied,” “class not registered,” or “internal failure occurred for unknown reasons” errors. The most common failure signature is the following:

  Exception type: System.UnauthorizedAccessException

  Message: Access is denied. (Exception from HRESULT: 0x80070005 (E_ACCESSDENIED))

  For more information about this issue, see the following article in the Microsoft Knowledge Base: 

  4345913 "Access Denied" errors and applications with COM activation fail after installing July 2018 Security and Quality Rollup updates for .NET Framework

  To resolve this issue, install the August Security Only update KB 4345681.

• Assume that you run the Azure Active Directory (Azure AD) Connect Health for Sync monitoring agent on a system that has .NET Framework 4.7.2 or the July 2018 updates for .NET Framework 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, or 4.7.2 installed. In this scenario, the system may experience slow performance and high CPU usage.
  
  For more information about this issue, see the following article in the Microsoft Knowledge Base:

  4457331 Slow performance and high CPU usage in Azure AD Connect Health for Sync monitoring agent on a system that has installed .NET Framework 4.7.2 or the July 2018 updates for .NET Framework 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, or 4.7.2

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, click Administrative Tools, and then click Microsoft Windows Server Update Services 3.0.
2. Expand ComputerName, and then click Action.
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 ActiveX control is installed, you see the Microsoft Update Catalog screen. Type 4340006 in the Search box, and then click Search.
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 require, click View Basket.
8. To import the packages to your WSUS server, click Import.
9. After the packages are imported, click Close to return to WSUS.

The updates are now available for installation through WSUS.

Update deployment information

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

20180710 Security update deployment information: July 10, 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.

• 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