Description of the Security Only update for .NET Framework 4.6, 4.6.1, 4.6.2, 4.7 and 4.7.1 for Windows 8.1, RT 8.1 and Server 2012 R2 (KB 4096236)

Summary

This update resolves a vulnerability in Microsoft .NET Framework that could allow a Denial of Service attack when .NET Framework and .NET core components process XML documents incorrectly. An attacker who successfully exploits this vulnerability could cause a denial of service against a .NET Framework application. To learn more about this vulnerability, see Microsoft Common Vulnerabilities and Exposures CVE-2018-0765.

Additionally, this update resolves a security feature bypass vulnerability in Windows that could allow an attacker to bypass Device Guard. An attacker who successfully exploits this vulnerability could circumvent a User Mode Code Integrity (UMCI) policy on the computer. To learn more about this vulnerability, see Microsoft Common Vulnerabilities and Exposures CVE-2018-1039.

Important

All updates for Windows RT 8.1, Windows 8.1, and Windows Server 2012 R2 require update 2 919355 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.

Quality and reliability improvements

CLR¹

Fixed a floating-point overflow in the thread pool’s hill climbing algorithm.

When you observe high CPU usage by ntoskrnl!KiPageFault that originates from BGC (as indicated by the clr!*gc_heap::bgc_thread_function), you might want this change so that the GC no longer uses the OS-implemented GetWriteWatch function to track BGC heap modifications. That process is very expensive because each of these page faults must take a process-wide lock. This is especially noticeable in the recent versions of the OS. You are probably seeing that most of the CPU is spent in the ntoskrnl!ExpWaitForSpinLockExclusiveAndAcquire function. This fix makes GC use CLR’s own implementation of the GetWriteWatch function instead.

¹ Common Language Runtime (CLR)

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:

4099639 Security Only update for .NET Framework 3.5 SP1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, and 4.7.1 updates for Windows 8.1, RT 8.1 and Server 2012 R2 (KB 4099639)

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:

Click Start, click Administrative Tools, and then click Microsoft Windows Server Update Services 3.0.
Expand ComputerName, and then click Action.
Click Import Updates.
WSUS opens a browser window in which you may be prompted to install an ActiveX control. You must install the ActiveX control to continue.
After the control is installed, you see the Microsoft Update Catalog screen. Enter 4099639 into the Search box, and then click Search.
Locate the .NET Framework packages that match the operating systems, languages, and processors in your environment. Click Add to add them to your basket.
After you select all the packages that you need, click View Basket.
To import the packages to your WSUS server, click Import.
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, go to the following article in the Microsoft Knowledge Base:

20180508 Security update deployment information: May 8, 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
The English (United States) version of this software update 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.

Windows 8.1, Windows RT 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-KB4096236-x64.msu	C554E9B37B66D99472BAA3F6C2407C722D801418	D1F33BBAF31AC3F52719C499482079CB6EA64C9EFB5344B18CDBD0F76B90AD81
Windows8.1-KB4096236-arm.msu	29073361787DEB656FC66BD8289E018D8243511A	341D893A3BEEAEDA2642B8580D43363414603C06D1DD2E9025FE048F4FCB92DB
Windows8.1-KB4096236-x86.msu	FE0514D5CF1DAF91DD79F24CD8FDA7375B61C2AC	95AD475FDD1D6027A54640682ACE31EFBAB37223C11304024C6836DE61593A80

For all supported x64-based versions

File name	File version	File size	Date	Time
mscorlib.dll	4.7.2650.0	5,413,520	21-Mar-2018	04:40
normidna.nlp		59,342	19-Oct-2017	03:38
normnfc.nlp		47,076	19-Oct-2017	03:38
normnfd.nlp		40,566	19-Oct-2017	03:38
normnfkc.nlp		67,808	19-Oct-2017	03:38
normnfkd.nlp		61,718	19-Oct-2017	03:38
clrjit.dll	4.7.2650.0	1,208,456	21-Mar-2018	04:40
clr.dll	4.7.2650.0	10,361,472	21-Mar-2018	04:40
compatjit.dll	4.7.2650.0	1,259,664	21-Mar-2018	04:40
mscordacwks.dll	4.7.2650.0	1,838,240	21-Mar-2018	04:40
mscordbi.dll	4.7.2650.0	1,621,136	21-Mar-2018	04:40
mscorlib.ni.dll	4.7.2650.0	22,646,336	21-Mar-2018	04:49
msvcp120_clr0400.dll	12.0.52519.0	690,008	26-Mar-2018	17:19
msvcr120_clr0400.dll	12.0.52519.0	993,632	26-Mar-2018	17:19
peverify.dll	4.7.2650.0	260,240	21-Mar-2018	04:40
sos.dll	4.7.2650.0	872,056	21-Mar-2018	04:40
system.security.dll	4.7.2650.0	324,696	21-Mar-2018	04:49
system.security.dll	4.7.2650.0	324,696	21-Mar-2018	04:49
mscorlib.dll	4.7.2650.0	5,631,624	21-Mar-2018	04:49
normidna.nlp		59,342	19-Oct-2017	03:38
normnfc.nlp		47,076	19-Oct-2017	03:38
normnfd.nlp		40,566	19-Oct-2017	03:38
normnfkc.nlp		67,808	19-Oct-2017	03:38
normnfkd.nlp		61,718	19-Oct-2017	03:38
clrjit.dll	4.7.2650.0	522,888	21-Mar-2018	04:49
clr.dll	4.7.2650.0	7,240,320	21-Mar-2018	04:49
mscordacwks.dll	4.7.2650.0	1,341,088	21-Mar-2018	04:49
mscordbi.dll	4.7.2650.0	1,167,504	21-Mar-2018	04:49
mscorlib.ni.dll	4.7.2650.0	20,521,528	21-Mar-2018	04:49
msvcp120_clr0400.dll	12.0.52519.0	485,576	26-Mar-2018	17:19
msvcr120_clr0400.dll	12.0.52519.0	987,840	26-Mar-2018	17:19
peverify.dll	4.7.2650.0	188,560	21-Mar-2018	04:49
sos.dll	4.7.2650.0	743,544	21-Mar-2018	04:49

For all supported ARM-based versions

File name	File version	File size	Date	Time
mscorlib.dll	4.7.2650.0	5,632,904	21-Mar-2018	04:37
normidna.nlp		59,342	19-Oct-2017	03:38
normnfc.nlp		47,076	19-Oct-2017	03:38
normnfd.nlp		40,566	19-Oct-2017	03:38
normnfkc.nlp		67,808	19-Oct-2017	03:38
normnfkd.nlp		61,718	19-Oct-2017	03:38
clrjit.dll	4.7.2650.0	686,976	21-Mar-2018	04:37
clr.dll	4.7.2650.0	6,739,320	21-Mar-2018	04:37
mscordacwks.dll	4.7.2650.0	1,295,768	21-Mar-2018	04:37
mscordbi.dll	4.7.2650.0	1,130,384	21-Mar-2018	04:37
mscorlib.ni.dll	4.7.2650.0	20,718,136	21-Mar-2018	04:49
msvcp120_clr0400.dll	12.0.52242.36242	602,080	26-Mar-2018	17:19
msvcr120_clr0400.dll	12.0.52242.36242	634,336	26-Mar-2018	17:19
sos.dll	4.7.2650.0	648,568	21-Mar-2018	04:37
system.security.dll	4.7.2650.0	324,696	21-Mar-2018	04:49

For all supported x86-based versions

File name	File version	File size	Date	Time
system.security.dll	4.7.2650.0	324,696	21-Mar-2018	04:49
mscorlib.dll	4.7.2650.0	5,631,624	21-Mar-2018	04:49
normidna.nlp		59,342	19-Oct-2017	03:38
normnfc.nlp		47,076	19-Oct-2017	03:38
normnfd.nlp		40,566	19-Oct-2017	03:38
normnfkc.nlp		67,808	19-Oct-2017	03:38
normnfkd.nlp		61,718	19-Oct-2017	03:38
clrjit.dll	4.7.2650.0	522,888	21-Mar-2018	04:49
clr.dll	4.7.2650.0	7,240,320	21-Mar-2018	04:49
mscordacwks.dll	4.7.2650.0	1,341,088	21-Mar-2018	04:49
mscordbi.dll	4.7.2650.0	1,167,504	21-Mar-2018	04:49
mscorlib.ni.dll	4.7.2650.0	20,521,528	21-Mar-2018	04:49
msvcp120_clr0400.dll	12.0.52519.0	485,576	26-Mar-2018	17:19
msvcr120_clr0400.dll	12.0.52519.0	987,840	26-Mar-2018	17:19
peverify.dll	4.7.2650.0	188,560	21-Mar-2018	04:49
sos.dll	4.7.2650.0	743,544	21-Mar-2018	04:49

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