MS16-077: Description of the security update for WPAD: June 14, 2016

Applies To
Windows Server 2012 R2 Datacenter Windows Server 2012 R2 Standard Windows Server 2012 R2 Essentials Windows Server 2012 R2 Foundation Windows 8.1 Enterprise Windows 8.1 Pro Windows 8.1 Windows RT 8.1 Windows Server 2012 Datacenter Windows Server 2012 Datacenter Windows Server 2012 Standard Windows Server 2012 Standard Windows Server 2012 Essentials Windows Server 2012 Foundation Windows Server 2012 Foundation Windows Server 2008 R2 Service Pack 1 Windows Server 2008 R2 Datacenter Windows Server 2008 R2 Enterprise Windows Server 2008 R2 Standard Windows Server 2008 R2 Web Edition Windows Server 2008 R2 Foundation Windows 7 Service Pack 1 Windows 7 Ultimate Windows 7 Enterprise Windows 7 Professional Windows 7 Home Premium Windows 7 Home Basic Windows 7 Starter Windows Server 2008 Service Pack 2 Windows Server 2008 Datacenter Windows Server 2008 Enterprise Windows Server 2008 Standard Windows Server 2008 Web Edition Windows Server 2008 Foundation Windows Server 2008 for Itanium-Based Systems Windows Vista Service Pack 2 Windows Vista Ultimate Windows Vista Enterprise Windows Vista Business Windows Vista Home Premium Windows Vista Home Basic Windows Vista Starter

Summary

This security update resolves vulnerabilities in Microsoft Windows. The vulnerabilities could allow elevation of privilege if the Web Proxy Auto Discovery (WPAD) protocol falls back to a vulnerable proxy discovery process on a target system. 

To learn more about the vulnerability, see Microsoft Security Bulletin MS16-077.

More Information

Important

  • All future security and non-security updates for Windows RT 8.1, 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 future updates.
  • 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.

Behavior changes after installation

After you install this security update, the following changes are applied:

  • NETBIOS communication outside of the local subnet is hardened. Therefore, by default, some features that depend on NETBIOS (such as SMB over NETBIOS) will not work outside the local subnet. To change this new default behavior, create the following registry entry:
    SUBKEY: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NetBT\Parameters
    Value Name: AllowNBToInternet
    Type: Dword
    Value: 1
    Default value of the flag: 0

  • By default, WPAD resolution for auto proxy detection will not use NETBIOS. Therefore, if proxy detection depends on NETBIOS alone for WPAD resolution, it may fail. We recommend that you use the DHCP option or DNS for WPAD resolution instead of NETBIOS. To change this new default behavior, create the following registry entry.

    Note This registry entry only applies for Windows 8.1 and earlier versions of Windows.

    SUBKEY: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\WinHttp
    Value Name: AllowOnlyDNSQueryForWPAD
    Type: DWORD
    Value: 0
    Default value of the flag: 1

  • The default behavior of PAC file download is changed so that the client's domain credentials are not automatically sent in response to an NTLM or Negotiate Authentication challenge when WinHTTP requests the PAC file. This occurs regardless of the value of the fAutoLogonIfChallenged flag that is specified in WINHTTP_AUTOPROXY_OPTIONS. To change this new default behavior, create the following registry entry:

    Note This registry entry only applies for Windows 8.1 and earlier versions of Windows.

    SUBKEY: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\WinHttp
    Value Name: AutoProxyAutoLogonIfChallenged
    Type: DWORD
    Value: 1
    Default value of the flag: 0

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 turn on automatic updating, see
Get security updates automatically.

Note For Windows RT 8.1, this update is available through Windows Update only.

Method 2: Microsoft Download Center

You can obtain the stand-alone update package through the Microsoft Download Center. Follow the installation instructions on the download page to install the update.

Click the download link in Microsoft Security Bulletin MS16-077 that corresponds to the version of Windows that you are running.

More Information

How to obtain help and support for this security update

Help for installing updates: Support for Microsoft Update

Security solutions for IT professionals: TechNet Security Troubleshooting and Support

Help for protecting your Windows-based computer from viruses and malware: Virus Solution and Security Center

Local support according to your country: International Support

File Information

File hash information
File name SHA1 hash SHA256 hash
Windows8.1-KB3161949-x86.msu A15B1E6C4E2D8C061C13AD6697340030D11300F9 684F04EC92FDB71A0587910F5223F29B1B1126E69B049EA4E6C1AB3E32BCD103
Windows8.1-KB3161949-x64.msu 303F894A71FAD84F147E1EE715F8C60DDFC752D7 39F78CC8472AA4ACB6AF6BD18CC13BDEFB9728ED71FCEE2001E063683FED2B50
Windows8-RT-KB3161949-x64.msu FD0D730F70653946886E358E9896364816937500 86967AF0963599C4E49835B35EF3A8A6BFA39FCBCB3C6DA378D02E70F34A023C
Windows6.0-KB3161949-x64.msu E60F107F4F893C19885931B3C6121FDDF1150E52 D2F0E848E7D45C428324DD6833CE1F6B9E36F4EC0C27FA33993B482C20A870E0
Windows6.0-KB3161949-x86.msu 45C230D3302716D81E413BD233F953BD6F6F1F09 B45C8FB5F7E96CE551E752F67E45AAB6657B9E204C603F23AA7284BB39FA3E8D
Windows6.1-KB3161949-x86.msu 0055D0D1E103D374E042F31EBDD26931853B882B F968AB471633DB7EBAF2619902CBB6246D14B14AF6E29CCA6C2981EB898DE0B7
Windows6.1-KB3161949-ia64.msu 9136B0FC403D6CDCD8CF94B061953CC11723CADB 7A2FFB83D4CE22325768FF94C71A9FFE839C653D1B8EA2C3BA73DDF89B2555C8
Windows6.1-KB3161949-x64.msu E2372FB5746E9474CEC6EF1710F8D58EC5C6C000 7CFC5DCDDD7A72E1CB143E41A98D5EAF23CE554104F05311EFD8B317BCE8E847
Windows6.0-KB3161949-ia64.msu 2F913DA164CBAD6FD4331A9D06BA3F457EC6887F 540668B9660A8CD03240B7DCF84A9DFAEBCCBE3C4661340389FB0A049F317825

      

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 times for these files are listed in Coordinated Universal Time (UTC). Be aware that dates and times for these files on your local computer are displayed in your local time and with your current daylight saving time bias. The dates and times may also change when you perform certain operations on the files.

Windows 8.1 and Windows Server 2012 R2 file information

Notes

  • The files that apply to a specific product, milestone (RTM, SPn), and service branch (LDR, GDR) can be identified by examining the file version numbers as shown in the following table:

    Version Product Milestone Service branch
    6.3.960 0.16 xxx Windows RT 8.1, Windows 8.1, and Windows Server 2012 R2 RTM GDR
    6.3.960 0.17 xxx Windows RT 8.1, Windows 8.1, and Windows Server 2012 R2 RTM GDR
    6.3.960 0.18 xxx Windows RT 8.1, Windows 8.1, and Windows Server 2012 R2 RTM GDR

  • GDR service branches contain only those fixes that are widely released to address widespread, critical issues. LDR service branches contain hotfixes in addition to widely released fixes.

  • The MANIFEST files (.manifest) and MUM files (.mum) that are installed are not listed.

For all supported x86-based versions

File name File version File size Date Time Platform SP requirement Service branch
Netbt.sys 6.3.9600.18340 213,504 13-May-2016 22:22 x86 None Not applicable
Mswsock.dll 6.3.9600.18340 286,208 13-May-2016 21:35 x86 SP_ X86_MICROSOFT-WINDOWS-W..-INFRASTRUCTURE-BSP
Ws2_32.dll 6.3.9600.18340 320,720 14-May-2016 20:01 x86 None Not applicable
Winhttp.dll 6.3.9600.18340 631,808 13-May-2016 21:26 x86 None Not applicable

For all supported x64-based versions

File name File version File size Date Time Platform SP requirement Service branch
Netbt.sys 6.3.9600.18340 281,088 13-May-2016 23:07 x64 None Not applicable
Mswsock.dll 6.3.9600.18340 339,456 13-May-2016 21:58 x64 SP_ AMD64_MICROSOFT-WINDOWS-W..-INFRASTRUCTURE-BSP
Ws2_32.dll 6.3.9600.18340 363,104 14-May-2016 20:01 x64 None Not applicable
Winhttp.dll 6.3.9600.18340 802,816 13-May-2016 21:45 x64 None Not applicable
Winhttp.dll 6.3.9600.18340 631,808 13-May-2016 21:26 x86 None Not applicable
Mswsock.dll 6.3.9600.18340 286,208 13-May-2016 21:35 x86 SP_ X86_MICROSOFT-WINDOWS-W..-INFRASTRUCTURE-BSP
Ws2_32.dll 6.3.9600.18340 320,720 14-May-2016 20:01 x86 None Not applicable

Windows Server 2012 file information

Notes

  • The files that apply to a specific product, milestone (RTM, SPn), and service branch (LDR, GDR) can be identified by examining the file version numbers as shown in the following table:

    Version Product Milestone Service branch
    6.2.920 0.17xxx Windows 8, Windows RT, or Windows Server 2012 RTM GDR
    6.2.920 0.21xxx Windows 8, Windows RT, or Windows Server 2012 RTM LDR

  • GDR service branches contain only those fixes that are widely released to address widespread, critical issues. LDR service branches contain hotfixes in addition to widely released fixes.

  • The MANIFEST files (.manifest) and MUM files (.mum) that are installed are not listed.

For all supported x64-based versions

File name File version File size Date Time Platform SP requirement Service branch
Netbt.sys 6.2.9200.21859 318,976 09-May-2016 13:19 x64 None Not applicable
Mswsock.dll 6.2.9200.21858 355,328 09-May-2016 15:41 x64 SP_ AMD64_MICROSOFT-WINDOWS-W..-INFRASTRUCTURE-BSP
Ws2_32.dll 6.2.9200.21858 343,552 09-May-2016 15:41 x64 None Not applicable
Winhttp.dll 6.2.9200.21858 711,680 09-May-2016 15:41 x64 None Not applicable
Winhttp.dll 6.2.9200.21797 516,096 08-Mar-2016 16:04 x86 None Not applicable
Mswsock.dll 6.2.9200.21858 288,768 09-May-2016 16:38 x86 SP_ X86_MICROSOFT-WINDOWS-W..-INFRASTRUCTURE-BSP
Ws2_32.dll 6.2.9200.21858 307,712 09-May-2016 16:39 x86 None Not applicable

Windows Vista and Windows Server 2008 file information

Notes

  • The files that apply to a specific product, milestone (RTM, SPn), and service branch (LDR, GDR) can be identified by examining the file version numbers as shown in the following table:

    Version Product Milestone Service branch
    6.0.600 2.19xxx Windows Vista or Windows Server 2008 SP2 GDR
    6.0.600 2.23xxx Windows Vista or Windows Server 2008 SP2 LDR

  • GDR service branches contain only those fixes that are widely released to address widespread, critical issues. LDR service branches contain hotfixes in addition to widely released fixes.

  • The MANIFEST files (.manifest) and MUM files (.mum) that are installed are not listed.

For all supported x64-based versions

File name File version File size Date Time Platform SP requirement Service branch
Netbt.sys 6.0.6002.19655 248,320 10-May-2016 14:55 x64 None Not applicable
Netbtugc.exe 6.0.6002.19655 24,064 10-May-2016 14:55 x64 None Not applicable
Netbt.sys 6.0.6002.23970 248,320 10-May-2016 14:53 x64 None Not applicable
Netbtugc.exe 6.0.6002.23970 24,064 10-May-2016 14:53 x64 None Not applicable
Mswsock.dll 6.0.6002.19655 304,128 10-May-2016 15:54 x64 SP_ AMD64_MICROSOFT-WINDOWS-W..-INFRASTRUCTURE-BSP
Mswsock.dll 6.0.6002.23970 303,616 10-May-2016 15:34 x64 SP_ AMD64_MICROSOFT-WINDOWS-W..-INFRASTRUCTURE-BSP
Ws2_32.dll 6.0.6002.19655 264,704 10-May-2016 15:55 x64 None Not applicable
Ws2_32.dll 6.0.6002.23970 264,704 10-May-2016 15:35 x64 None Not applicable
Winhttp.dll 6.0.6002.19655 442,880 10-May-2016 15:54 x64 None Not applicable
Winhttp.dll 6.0.6002.23970 442,880 10-May-2016 15:35 x64 None Not applicable
Netbtugc.exe 6.0.6002.19655 21,504 10-May-2016 14:28 x86 None Not applicable
Netbtugc.exe 6.0.6002.23970 21,504 10-May-2016 14:28 x86 None Not applicable
Winhttp.dll 6.0.6002.19655 377,344 10-May-2016 15:31 x86 None Not applicable
Winhttp.dll 6.0.6002.23970 377,344 10-May-2016 15:14 x86 None Not applicable
Mswsock.dll 6.0.6002.19655 223,232 10-May-2016 15:31 x86 SP_ X86_MICROSOFT-WINDOWS-W..-INFRASTRUCTURE-BSP
Mswsock.dll 6.0.6002.23970 223,232 10-May-2016 15:14 x86 SP_ X86_MICROSOFT-WINDOWS-W..-INFRASTRUCTURE-BSP
Ws2_32.dll 6.0.6002.19655 179,200 10-May-2016 15:31 x86 None Not applicable
Ws2_32.dll 6.0.6002.23970 179,200 10-May-2016 15:14 x86 None Not applicable

For all supported x86-based versions

File name File version File size Date Time Platform SP requirement Service branch
Netbt.sys 6.0.6002.19655 185,856 10-May-2016 14:28 x86 None Not applicable
Netbtugc.exe 6.0.6002.19655 21,504 10-May-2016 14:28 x86 None Not applicable
Netbt.sys 6.0.6002.23970 186,368 10-May-2016 14:28 x86 None Not applicable
Netbtugc.exe 6.0.6002.23970 21,504 10-May-2016 14:28 x86 None Not applicable
Mswsock.dll 6.0.6002.19655 223,232 10-May-2016 15:31 x86 SP_ X86_MICROSOFT-WINDOWS-W..-INFRASTRUCTURE-BSP
Mswsock.dll 6.0.6002.23970 223,232 10-May-2016 15:14 x86 SP_ X86_MICROSOFT-WINDOWS-W..-INFRASTRUCTURE-BSP
Ws2_32.dll 6.0.6002.19655 179,200 10-May-2016 15:31 x86 None Not applicable
Ws2_32.dll 6.0.6002.23970 179,200 10-May-2016 15:14 x86 None Not applicable
Winhttp.dll 6.0.6002.19655 377,344 10-May-2016 15:31 x86 None Not applicable
Winhttp.dll 6.0.6002.23970 377,344 10-May-2016 15:14 x86 None Not applicable

For all supported ia64-based versions

File name File version File size Date Time Platform SP requirement Service branch
Netbt.sys 6.0.6002.19655 632,832 10-May-2016 14:37 IA-64 None Not applicable
Netbtugc.exe 6.0.6002.19655 52,224 10-May-2016 14:36 IA-64 None Not applicable
Netbt.sys 6.0.6002.23970 632,832 10-May-2016 14:38 IA-64 None Not applicable
Netbtugc.exe 6.0.6002.23970 52,224 10-May-2016 14:37 IA-64 None Not applicable
Mswsock.dll 6.0.6002.19655 709,632 10-May-2016 15:23 IA-64 SP_ IA64_MICROSOFT-WINDOWS-W..-INFRASTRUCTURE-BSP
Mswsock.dll 6.0.6002.23970 709,120 10-May-2016 15:12 IA-64 SP_ IA64_MICROSOFT-WINDOWS-W..-INFRASTRUCTURE-BSP
Ws2_32.dll 6.0.6002.19655 519,168 10-May-2016 15:23 IA-64 None Not applicable
Ws2_32.dll 6.0.6002.23970 519,168 10-May-2016 15:13 IA-64 None Not applicable
Winhttp.dll 6.0.6002.19655 962,048 10-May-2016 15:23 IA-64 None Not applicable
Winhttp.dll 6.0.6002.23970 962,048 10-May-2016 15:13 IA-64 None Not applicable
Netbtugc.exe 6.0.6002.19655 21,504 10-May-2016 14:28 x86 None Not applicable
Netbtugc.exe 6.0.6002.23970 21,504 10-May-2016 14:28 x86 None Not applicable
Winhttp.dll 6.0.6002.19655 377,344 10-May-2016 15:31 x86 None Not applicable
Winhttp.dll 6.0.6002.23970 377,344 10-May-2016 15:14 x86 None Not applicable
Mswsock.dll 6.0.6002.19655 223,232 10-May-2016 15:31 x86 SP_ X86_MICROSOFT-WINDOWS-W..-INFRASTRUCTURE-BSP
Mswsock.dll 6.0.6002.23970 223,232 10-May-2016 15:14 x86 SP_ X86_MICROSOFT-WINDOWS-W..-INFRASTRUCTURE-BSP
Ws2_32.dll 6.0.6002.19655 179,200 10-May-2016 15:31 x86 None Not applicable
Ws2_32.dll 6.0.6002.23970 179,200 10-May-2016 15:14 x86 None Not applicable

Windows 7 and Windows Server 2008 R2 file information

Notes

  • The files that apply to a specific product, milestone (RTM, SPn), and service branch (LDR, GDR) can be identified by examining the file version numbers as shown in the following table:

    Version Product Milestone Service branch
    6.1.760 1.18xxx Windows 7 or Windows Server 2008 R2 SP1 GDR
    6.1.760 1.23 xxx Windows 7 or Windows Server 2008 R2 SP1 LDR

  • GDR service branches contain only those fixes that are widely released to address widespread, critical issues. LDR service branches contain hotfixes in addition to widely released fixes.

  • The MANIFEST files (.manifest) and MUM files (.mum) that are installed are not listed.

For all supported x86-based versions

File name File version File size Date Time Platform SP requirement Service branch
Netbt.sys 6.1.7601.23451 188,928 11-May-2016 14:52 x86 None Not applicable
Netbtugc.exe 6.1.7601.23451 26,624 11-May-2016 15:01 x86 None Not applicable
Mswsock.dll 6.1.7601.23451 231,424 11-May-2016 15:19 x86 SP_ X86_MICROSOFT-WINDOWS-W..-INFRASTRUCTURE-BSP
Ws2_32.dll 6.1.7601.23451 206,336 11-May-2016 15:19 x86 None Not applicable
Winhttp.dll 6.1.7601.23451 351,744 11-May-2016 15:19 x86 None Not applicable

For all supported ia64-based versions

File name File version File size Date Time Platform SP requirement Service branch
Netbt.sys 6.1.7601.23451 616,960 11-May-2016 14:44 IA-64 None Not applicable
Netbtugc.exe 6.1.7601.23451 53,760 11-May-2016 14:58 IA-64 None Not applicable
Mswsock.dll 6.1.7601.23451 750,592 11-May-2016 15:13 IA-64 SP_ IA64_MICROSOFT-WINDOWS-W..-INFRASTRUCTURE-BSP
Ws2_32.dll 6.1.7601.23451 546,304 11-May-2016 15:13 IA-64 None Not applicable
Winhttp.dll 6.1.7601.23451 812,032 11-May-2016 15:13 IA-64 None Not applicable
Netbtugc.exe 6.1.7601.23451 26,624 11-May-2016 15:01 x86 None Not applicable
Winhttp.dll 6.1.7601.23451 351,744 11-May-2016 15:19 x86 None Not applicable
Mswsock.dll 6.1.7601.23451 231,424 11-May-2016 15:19 x86 SP_ X86_MICROSOFT-WINDOWS-W..-INFRASTRUCTURE-BSP
Ws2_32.dll 6.1.7601.23451 206,336 11-May-2016 15:19 x86 None Not applicable

For all supported x64-based versions

File name File version File size Date Time Platform SP requirement Service branch
Netbt.sys 6.1.7601.23451 262,144 11-May-2016 14:58 x64 None Not applicable
Netbtugc.exe 6.1.7601.23451 25,088 11-May-2016 15:11 x64 None Not applicable
Mswsock.dll 6.1.7601.23451 327,168 11-May-2016 17:02 x64 SP_ AMD64_MICROSOFT-WINDOWS-W..-INFRASTRUCTURE-BSP
Ws2_32.dll 6.1.7601.23451 296,448 11-May-2016 17:02 x64 None Not applicable
Winhttp.dll 6.1.7601.23451 444,928 11-May-2016 17:02 x64 None Not applicable
Netbtugc.exe 6.1.7601.23451 26,624 11-May-2016 15:01 x86 None Not applicable
Winhttp.dll 6.1.7601.23451 351,744 11-May-2016 15:19 x86 None Not applicable
Mswsock.dll 6.1.7601.23451 231,424 11-May-2016 15:19 x86 SP_ X86_MICROSOFT-WINDOWS-W..-INFRASTRUCTURE-BSP
Ws2_32.dll 6.1.7601.23451 206,336 11-May-2016 15:19 x86 None Not applicable