View products that this article applies to.

Summary

This security update for the Microsoft .NET Framework resolves a security feature bypass vulnerability when the .NET Framework (and the .NET Core) components don't completely validate certificates. To learn more about this vulnerability, see Microsoft Common Vulnerabilities and Exposures CVE-2017-0248.

This update also contains security-enhancing fixes to the Windows Presentation Framework PackageDigitalSignatureManager component's ability to sign packages with the SHA256 hash algorithm.

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

Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall the operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.

  • Enhanced Key Usage (EKU) is described in RFC 5280 in section 4.2.1.12: This extension indicates one or more purposes for which the certified public key may be used, in addition to or in place of the basic purposes that are indicated in the key usage extension. For example, a certificate that’s used for the authentication of a client to a server must be configured for Client Authentication. Similarly, a certificate that’s used for the authentication of a server must be configured for Server Authentication.

    When certificates are used for authentication, the authenticator examines the client certificate and seeks the correct purpose object identifier in Application Policies extensions. For example, the object identifier for Client Authentication is 1.3.6.1.5.5.7.3.2. When a certificate is used for client authentication, this object identifier must be present in the EKU extensions of the certificate or authentication fails. Certificates that have no EKU extension continue to authenticate correctly.

    If you temporarily can’t access correctly reissued certificates, you can choose to opt in or out of the security change across all computer operations to avoid any connectivity effects. To do this, specify the following registry key settings, depending on which .NET Framework version your application is targeting.

    Method 1: Updating registry key (available for all versions)

    Note This registry entry must be a DWORD entry.

    • For 32-bit process on 32-bit system and 64-bit process on 64-bit system:

      HKEY_LOCAL_MACHINE\Software\Microsoft\.NETFramework\v4.0.30319@RequireCertificateEKUs=0

    • For 32-bit process on 64-bit system:

      HKEY_LOCAL_MACHINE \Software\Wow6432Node\Microsoft\.NETFramework\v4.0.30319@RequireCertificateEKUs=0

    You can also opt out on a per-application basis. The following options are available for disabling this change to make sure that application compatibility is maintained.

    Method 2: Disable the policy for individual applications

    Note This registry entry must be a DWORD entry. The only valid value is 0. Any other value is ignored.

    • For 32-bit process on 32-bit system and 64-bit process on 64-bit system:

      HKEY_LOCAL_MACHINE\Software\Microsoft\.NETFramework\v4.0.30319@System.Net.ServicePointManager.RequireCertificateEKUs
      S:\Prj\console_pg\console_pg45\bin\Release\console_pg45.exe=0
      C:\MyApp\MyApp.exe=0

    • For 32-bit process on 64-bit system:

      HKEY_LOCAL_MACHINE \Software\Wow6432Node\Microsoft\.NETFramework\v4.0.30319@System.Net.ServicePointManager.RequireCertificateEKUs
      S:\Prj\console_pg\console_pg45\bin\Release\console_pg45.exe=0
      C:\MyApp\MyApp.exe=0

    Method 3: Using configuration API (available for the .NET Framework 4.6 and later versions)

    Starting in the .NET Framework 4.6, you can change the configuration at an application level through code, an application configuration, or registry changes.

    Configuring the switch in the .NET Framework 4.6

    Note The following examples disable the security feature.

    • Programmatically

      The first thing that the application should do is run the following code. This is because Service Point Manager initializes only one time.
        private const string DisableCachingName = @"TestSwitch.LocalAppContext.DisableCaching"; private const string DontCheckCertificateEKUsName= @"Switch.System.Net.DontCheckCertificateEKUs"; AppContext.SetSwitch(DisableCachingName, true); AppContext.SetSwitch(DontCheckCertificateEKUsName, true);

    • Application configuration

      To change the application configuration, add the following entry:
        <runtime> <AppContextSwitchOverrides value="Switch.System.Net.DontCheckCertificateEKUsName=true"/> </runtime>

    • Registry key (machine global):

      Registry location: HKEY_LOCAL_MACHINE\Software\[Wow6432Node\]Microsoft\.NETFramework\AppContext\Switch.System.Net.DontCheckCertificateEKUsName

      Type: String
      Value: "true"

    Note By default, Switch.System.Net.DontCheckCertificateEKUsName = True for all .NET Framework 4.x applications that are running on the .NET Framework 4.6 and later versions.

  • For more information about this security update as it relates to Windows 7 Service Pack 1 and Windows Server 2008 R2 Service Pack 1, see the following article in the Microsoft Knowledge Base:

    4019112 Security and Quality Rollup for the .NET Framework 3.5.1, 4.5.2, 4.6, 4.6.1, and 4.6.2 updates for Windows 7 Service Pack 1 and Windows Server 2008 R2 Service Pack 1: May 9, 2017

How to obtain and install the update

Method 1: Windows Update

This update is available through Windows Update. When you turn on automatic updating, this update will be downloaded and installed automatically. For more information about how to get security updates automatically, see Windows Update: FAQ.
 

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 will open a browser window in which you may be prompted to install an ActiveX control. You must install the ActiveX control to continue.

  5. Once the control is installed, you will see the Microsoft Update Catalog screen. Enter 4019112 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. When you have selected all the packages that you need, click View Basket.

  8. Click Import to import the packages to your WSUS server.

  9. Click Close once the packages have been imported 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:

20170509 Security update deployment information: May 9, 2017

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

Package Name

Package Hash SHA 1

Package Hash SHA 2

NDP46-KB4014508-x64.exe

BF8BC7D1D93CE7C4D2BB1DF260B48829DEDB56F1

2101D5065FA98EA1147E3790DB461ABD8E3C432A208AB5898E05CDC7B5F662F0

NDP46-KB4014508-x86.exe

4F1326EFE09B1CCBC400462831AB00D578756569

8A230568C772878AB3C221712ACAA9464C3C68D1D7C9D82362C46257B228CF08


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 systems

File name

File version

File size

Date

Time

PenIMC.dll

4.6.1647.0

81,560

29-Mar-2017

23:32

PresentationCore.dll

4.6.1647.0

3,521,880

29-Mar-2017

23:32

PresentationFramework.dll

4.6.1647.0

6,190,960

29-Mar-2017

23:32

PresentationHost_v0400.dll

4.6.1647.0

197,848

29-Mar-2017

23:32

PresentationNative_v0400.dll

4.6.1647.0

826,592

29-Mar-2017

23:32

System.Core.dll

4.6.1647.0

1,349,280

29-Mar-2017

23:31

System.Data.dll

4.6.1647.0

3,389,616

29-Mar-2017

23:31

System.dll

4.6.1647.0

3,506,824

29-Mar-2017

23:31

System.Management.dll

4.6.1647.0

415,432

29-Mar-2017

23:31

System.Windows.Controls.Ribbon.dll

4.6.1647.0

742,808

29-Mar-2017

23:32

System.Xaml.dll

4.6.1647.0

631,456

29-Mar-2017

23:32

WindowsBase.dll

4.6.1647.0

1,277,768

29-Mar-2017

23:32

WMINet_Utils.dll

4.6.1647.0

136,368

29-Mar-2017

23:31

WPFFontCache_v0400.exe

4.6.1647.0

25,720

29-Mar-2017

23:32

wpfgfx_v0400.dll

4.6.1647.0

1,759,920

29-Mar-2017

23:32

VsVersion.dll

14.6.1647.0

19,112

29-Mar-2017

23:31

For all x64-based systems

File name

File version

File size

Date

Time

PenIMC.dll

4.6.1647.0

97,432

29-Mar-2017

23:44

PenIMC.dll

4.6.1647.0

81,560

29-Mar-2017

23:32

PresentationCore.dll

4.6.1647.0

3,504,320

29-Mar-2017

23:44

PresentationCore.dll

4.6.1647.0

3,521,880

29-Mar-2017

23:32

PresentationFramework.dll

4.6.1647.0

6,190,960

29-Mar-2017

23:32

PresentationHost_v0400.dll

4.6.1647.0

254,680

29-Mar-2017

23:44

PresentationHost_v0400.dll

4.6.1647.0

197,848

29-Mar-2017

23:32

PresentationNative_v0400.dll

4.6.1647.0

1,107,680

29-Mar-2017

23:44

PresentationNative_v0400.dll

4.6.1647.0

826,592

29-Mar-2017

23:32

System.Core.dll

4.6.1647.0

1,349,280

29-Mar-2017

23:31

System.Data.dll

4.6.1647.0

3,454,640

29-Mar-2017

23:44

System.Data.dll

4.6.1647.0

3,389,616

29-Mar-2017

23:31

System.dll

4.6.1647.0

3,506,824

29-Mar-2017

23:31

System.Management.dll

4.6.1647.0

415,432

29-Mar-2017

23:31

System.Windows.Controls.Ribbon.dll

4.6.1647.0

742,808

29-Mar-2017

23:32

System.Xaml.dll

4.6.1647.0

631,456

29-Mar-2017

23:32

WindowsBase.dll

4.6.1647.0

1,277,768

29-Mar-2017

23:32

WMINet_Utils.dll

4.6.1647.0

188,080

29-Mar-2017

23:44

WMINet_Utils.dll

4.6.1647.0

136,368

29-Mar-2017

23:31

WPFFontCache_v0400.exe

4.6.1647.0

26,744

30-Mar-2017

01:32

WPFFontCache_v0400.exe

4.6.1647.0

25,720

29-Mar-2017

23:32

wpfgfx_v0400.dll

4.6.1647.0

2,262,712

29-Mar-2017

23:44

wpfgfx_v0400.dll

4.6.1647.0

1,759,920

29-Mar-2017

23:32

VsVersion.dll

14.6.1647.0

19,104

29-Mar-2017

23:44

VsVersion.dll

14.6.1647.0

19,112

29-Mar-2017

23:31

 

How to obtain help and support for this security update

Applies to

This article applies to the following:

  • Microsoft .NET Framework 4.6.2 when used with:

    • Windows Server 2008 R2 Service Pack 1

    • Windows 7 Service Pack 1

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!

×