Microsoft Security Bulletin MS16-063 - Critical

Cumulative Security Update for Internet Explorer (3163649)

Published: June 14, 2016 | Updated: June 22, 2016

Version: 1.1

Executive Summary

This security update resolves vulnerabilities in Internet Explorer. The most severe of the vulnerabilities could allow remote code execution if a user views a specially crafted webpage using Internet Explorer. An attacker who successfully exploited the vulnerabilities could gain the same user rights as the current user. If the current user is logged on with administrative user rights, an attacker could take control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

This security update is rated Critical for Internet Explorer 9 (IE 9), and Internet Explorer 11 (IE 11) on affected Windows clients, and Moderate for Internet Explorer 9 (IE 9), Internet Explorer 10 (IE 10), and Internet Explorer 11 (IE 11) on affected Windows servers. For more information, see the Affected Software section.

The update addresses the vulnerabilities by:

  • Modifying how Internet Explorer handles objects in memory
  • Modifying how the JScript and VBScript scripting engines handle objects in memory
  • Fixing how the Internet Explorer XSS Filter validates JavaScript
  • Correcting how Windows handles proxy discovery

For more information about the vulnerabilities, see the Vulnerability Information section.

For more information about this update, see Microsoft Knowledge Base Article 3163649.

Affected Software

The following software versions or editions are affected. Versions or editions that are not listed are either past their support life cycle or are not affected. To determine the support life cycle for your software version or edition, see Microsoft Support Lifecycle.

Operating System Component Maximum Security Impact Aggregate Severity Rating

Updates Replaced*

Internet Explorer 9
Windows Vista Service Pack 2 Internet Explorer 9
(3160005)
Remote Code Execution Critical 3154070 in MS16-051
Windows Vista x64 Edition Service Pack 2 Internet Explorer 9
(3160005)
Remote Code Execution Critical 3154070 in MS16-051
Windows Server 2008 for 32-bit Systems Service Pack 2 Internet Explorer 9
(3160005)
Remote Code Execution Moderate 3154070 in MS16-051
Windows Server 2008 for x64-based Systems Service Pack 2 Internet Explorer 9
(3160005)
Remote Code Execution Moderate 3154070 in MS16-051
Internet Explorer 10
Windows Server 2012 Internet Explorer 10 [1]
(3160005)
Remote Code Execution Moderate 3154070 in MS16-051
Internet Explorer 11
Windows 7 for 32-bit Systems Service Pack 1 Internet Explorer 11 (3160005) Remote Code Execution Critical 3154070 in MS16-051
Windows 7 for x64-based Systems Service Pack 1 Internet Explorer 11 (3160005) Remote Code Execution Critical 3154070 in MS16-051
Windows Server 2008 R2 for x64-based Systems Service Pack 1 Internet Explorer 11 [1]
(3160005)
Remote Code Execution Moderate 3154070 in MS16-051
Windows 8.1 for 32-bit Systems Internet Explorer 11 (3160005) Remote Code Execution Critical 3154070 in MS16-051
Windows 8.1 for x64-based Systems Internet Explorer 11 (3160005) Remote Code Execution Critical 3154070 in MS16-051
Windows Server 2012 R2 Internet Explorer 11 (3160005) Remote Code Execution Moderate 3154070 in MS16-051
Windows RT 8.1 Internet Explorer 11 [1] [2] (3160005) Remote Code Execution Critical 3154070 in MS16-051
Windows 10 for 32-bit Systems [3] (3163017) Internet Explorer 11 Remote Code Execution Critical 3156387
Windows 10 for x64-based Systems [3] (3163017) Internet Explorer 11 Remote Code Execution Critical 3156387
Windows 10 Version 1511 for 32-bit Systems [3] (3163018) Internet Explorer 11 Remote Code Execution Critical 3156421
Windows 10 Version 1511 for x64-based Systems [3] (3163018) Internet Explorer 11 Remote Code Execution Critical 3156421

[1]For information about changes in support for Internet Explorer beginning January 12, 2016, see Microsoft Support Lifecycle.

[2]This update is available via Windows Update.

[3]Windows 10 updates are cumulative. The monthly security release includes all security fixes for vulnerabilities that affect Windows 10, in addition to non-security updates. The updates are available via the Microsoft Update Catalog.

Note Windows Server 2016 Technical Preview 5 is affected. Customers running this operating system are encouraged to apply the update, which is available via Windows Update.

*The Updates Replaced column shows only the latest update in any chain of superseded updates. For a comprehensive list of updates replaced, go to the Microsoft Update Catalog, search for the update KB number, and then view update details (updates replaced information is provided on the Package Details tab).

Update FAQ

Does this update contain any additional security-related changes to functionality?
In addition to the changes that are listed for the vulnerabilities described in this bulletin, this update includes defense-in-depth updates to help improve security-related features.

For my particular system and Internet Explorer configuration, which update addresses the vulnerabilities discussed in CVE-2016-3205, CVE-2016-3206, and CVE-2016-3207?
CVE-2016-3205, CVE-2016-3206, and CVE-2016-3207 are vulnerabilities in the VBScript engine. Although the attack vector is through Internet Explorer, the vulnerability is addressed by the updates released in this bulletin (MS16-063) for systems running Internet Explorer 9, Internet Explorer 10, and Internet Explorer 11. For Internet Explorer 7 and earlier, the vulnerabilities are addressed by the updates described in MS16-069.

Are there any further steps I need to carry out to be protected from CVE-2016-3213 described in this bulletin?
Yes. It is important to note that the security update described in this bulletin for CVE-2016-3213 does not fully protect your system. You must also install the update in MS16-077 to be fully protected from this vulnerability.

Severity Ratings and Vulnerability Identifiers

The following severity ratings assume the potential maximum impact of the vulnerability. For information regarding the likelihood, within 30 days of this security bulletin's release, of the exploitability of the vulnerability in relation to its severity rating and security impact, please see the Exploitability Index in the June bulletin summary.

Where specified in the Severity Ratings and Impact table, Critical, Important, and Moderate values indicate severity ratings. For more information, see Security Bulletin Severity Rating System. Refer to the following key for the abbreviations used in the table to indicate maximum impact:

Abbreviation Maximum Impact
RCE Remote Code Execution
EoP Elevation of Privilege
ID Information Disclosure
SFB Security Feature Bypass

Vulnerability Severity Ratings and Impact
CVE number Vulnerability title Internet Explorer 9 Internet Explorer 10 Internet Explorer 11 Internet Explorer 11
on Windows 10
CVE-2016-0199 Internet Explorer Memory Corruption Vulnerability Windows Clients:
Critical / RCE
Windows Servers
Moderate/ RCE
Windows Clients:
Critical / RCE
Windows Servers
Moderate/ RCE
Windows Clients:
Critical / RCE
Windows Servers
Moderate/ RCE
Windows Clients:
Critical / RCE
Windows Servers
Moderate/ RCE
CVE-2016-0200 Internet Explorer Memory Corruption Vulnerability Windows Clients:
Critical / RCE
Windows Servers
Moderate/ RCE
Windows Clients:
Critical / RCE
Windows Servers
Moderate/ RCE
Windows Clients:
Critical / RCE
Windows Servers
Moderate/ RCE
Windows Clients:
Critical / RCE
Windows Servers
Moderate/ RCE
CVE-2016-3202 Scripting Engine Memory Corruption Vulnerability Not applicable Windows Clients:
Critical / RCE
Windows Servers
Moderate/ RCE
Windows Clients:
Critical / RCE
Windows Servers
Moderate/ RCE
Windows Clients:
Critical / RCE
Windows Servers
Moderate/ RCE
CVE-2016-3205 Scripting Engine Memory Corruption Vulnerability Windows Clients:
Critical / RCE
Windows Servers
Moderate/ RCE
Windows Clients:
Critical / RCE
Windows Servers
Moderate/ RCE
Windows Clients:
Critical / RCE
Windows Servers
Moderate/ RCE
Windows Clients:
Critical / RCE
Windows Servers
Moderate/ RCE
CVE-2016-3206 Scripting Engine Memory Corruption Vulnerability Windows Clients:
Critical / RCE
Windows Servers
Moderate/ RCE
Windows Clients:
Critical / RCE
Windows Servers
Moderate/ RCE
Windows Clients:
Critical / RCE
Windows Servers
Moderate/ RCE
Windows Clients:
Critical / RCE
Windows Servers
Moderate/ RCE
CVE-2016-3207 Scripting Engine Memory Corruption Vulnerability Windows Clients:
Critical / RCE
Windows Servers
Moderate/ RCE
Windows Clients:
Critical / RCE
Windows Servers
Moderate/ RCE
Windows Clients:
Critical / RCE
Windows Servers
Moderate/ RCE
Windows Clients:
Critical / RCE
Windows Servers
Moderate/ RCE
CVE-2016-3210 Scripting Engine Memory Corruption Vulnerability Not applicable Not applicable Windows Clients:
Critical / RCE
Windows Servers
Moderate/ RCE
Windows Clients:
Critical / RCE
Windows Servers
Moderate/ RCE
CVE-2016-3211 Internet Explorer Memory Corruption Vulnerability Windows Clients:
Important / RCE
Windows Servers
Low / RCE
Windows Clients:
Important / RCE
Windows Servers
Low / RCE
Windows Clients:
Important / RCE
Windows Servers
Low / RCE
Windows Clients:
Important / RCE
Windows Servers
Low / RCE
CVE-2016-3212 Internet Explorer XSS Filter Vulnerability Windows Clients:
Important / RCE
Windows Servers
Low / RCE
Windows Clients:
Important / RCE
Windows Servers
Low / RCE
Windows Clients:
Important / RCE
Windows Servers
Low / RCE
Windows Clients:
Important / RCE
Windows Servers
Low / RCE
CVE-2016-3213 WPAD Elevation of Privilege Vulnerability Windows Clients:
Important / EoP
Windows Servers
Low / EoP
Windows Clients:
Important / EoP
Windows Servers
Low / EoP
Windows Clients:
Important / EoP
Windows Servers
Low / EoP
Windows Clients:
Important / EoP
Windows Servers
Low / EoP

Vulnerability Information

Microsoft Internet Explorer Memory Corruption Vulnerabilities

Remote code execution vulnerabilities exist when Internet Explorer improperly accesses objects in memory. The vulnerabilities could corrupt memory in such a way that an attacker could execute arbitrary code in the context of the current user. An attacker who successfully exploited the vulnerabilities could gain the same user rights as the current user. If the current user is logged on with administrative user rights, the attacker could take control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

An attacker could host a specially crafted website that is designed to exploit the vulnerabilities through Internet Explorer, and then convince a user to view the website. The attacker could also take advantage of compromised websites, or websites that accept or host user-provided content or advertisements, by adding specially crafted content that could exploit the vulnerabilities. In all cases, however, an attacker would have no way to force users to view the attacker-controlled content. Instead, an attacker would have to convince users to take action, typically by an enticement in an email or Instant Messenger message, or by getting them to open an attachment sent through email. The update addresses the vulnerabilities by modifying how Internet Explorer handles objects in memory.

The following table contains links to the standard entry for each vulnerability in the Common Vulnerabilities and Exposures list:

Vulnerability title CVE number Publicly disclosed Exploited
Internet Explorer Memory Corruption Vulnerability CVE-2016-0199 No No
Internet Explorer Memory Corruption Vulnerability CVE-2016-0200 No No
Internet Explorer Memory Corruption Vulnerability CVE-2016-3211 No No

Mitigating Factors

Microsoft has not identified any mitigating factors for this vulnerability.

Workarounds

Microsoft has not identified any workarounds for this vulnerability.

FAQ

I am running Internet Explorer on Windows Server 2008, Windows Server 2008 R2, Windows Server 2012, or Windows Server 2012 R2. Does this mitigate these vulnerabilities?
Yes. By default, Internet Explorer on Windows Server 2008, Windows Server 2008 R2, Windows Server 2012, and Windows Server 2012 R2 runs in a restricted mode that is known as Enhanced Security Configuration. Enhanced Security Configuration is a group of preconfigured settings in Internet Explorer that can reduce the likelihood of a user or administrator downloading and running specially crafted web content on a server. This is a mitigating factor for websites that you have not added to the Internet Explorer Trusted sites zone.

Can EMET help mitigate attacks that attempt to exploit these vulnerabilities?
Yes. The Enhanced Mitigation Experience Toolkit (EMET) enables users to manage security mitigation technologies that help make it more difficult for attackers to exploit memory corruption vulnerabilities in a given piece of software. EMET can help mitigate attacks that attempt to exploit these vulnerabilities in Internet Explorer on systems where EMET is installed and configured to work with Internet Explorer.

For more information about EMET, see the Enhanced Mitigation Experience Toolkit.

Multiple Scripting Engine Memory Corruption Vulnerabilities

Multiple remote code execution vulnerabilities exist in the way that the JScript 9, JScript, and VBScript engines render when handling objects in memory in Internet Explorer. The vulnerabilities could corrupt memory in such a way that an attacker could execute arbitrary code in the context of the current user. An attacker who successfully exploited the vulnerabilities could gain the same user rights as the current user. If the current user is logged on with administrative user rights, an attacker who successfully exploited the vulnerabilities could take control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

In a web-based attack scenario, an attacker could host a specially crafted website that is designed to exploit the vulnerabilities through Internet Explorer and then convince a user to view the website. An attacker could also embed an ActiveX control marked "safe for initialization" in an application or Microsoft Office document that hosts the IE rendering engine. The attacker could also take advantage of compromised websites, and websites that accept or host user-provided content or advertisements. These websites could contain specially crafted content that could exploit the vulnerabilities. The update addresses the vulnerabilities by modifying how the JScript 9, JScript, and VBScript scripting engines handle objects in memory.

The following table contains links to the standard entry for each vulnerability in the Common Vulnerabilities and Exposures list:

Vulnerability title CVE number Publicly disclosed Exploited
Scripting Engine Memory Corruption Vulnerability CVE-2016-3202 No No
Scripting Engine Memory Corruption Vulnerability CVE-2016-3205 No No
Scripting Engine Memory Corruption Vulnerability CVE-2016-3206 No No
Scripting Engine Memory Corruption Vulnerability CVE-2016-3207 No No
Scripting Engine Memory Corruption Vulnerability CVE-2016-3210 No No

Mitigating Factors

Microsoft has not identified any mitigating factors for this vulnerability.

Workarounds

The following workaround may be helpful in your situation:

  • Restrict access to VBScript.dll and JScript.dll

    • For 32-bit systems, enter the following command at an administrative command prompt:

          takeown /f %windir%\system32\vbscript.dll   
          cacls %windir%\system32\vbscript.dll /E /P everyone:N  
          cacls %windir%\system32\jscript.dll /E /P everyone:N
      
    • For 64-bit systems, enter the following command at an administrative command prompt:

          takeown /f %windir%\syswow64\vbscript.dll   
          cacls %windir%\syswow64\vbscript.dll /E /P everyone:N  
          cacls %windir%\syswow64\jscript.dll /E /P everyone:N
      

    Impact of Workaround. Websites that use VBScript or JScript may not work properly.

    How to undo the workaround.

    • For 32-bit systems, enter the following command at an administrative command prompt:

          cacls %windir%\system32\vbscript.dll /E /R everyone  
          cacls %windir%\system32\jscript.dll /E /R everyone
      
    • For 64-bit systems, enter the following command at an administrative command prompt:

          cacls %windir%\syswow64\vbscript.dll /E /R everyone  
          cacls %windir%\syswow64\jscript.dll /E /R everyone
      

Internet Explorer XSS Filter Vulnerability - CVE-2016-3212

A remote code execution vulnerability exists when the Internet Explorer XSS Filter does not properly validate JavaScript under specific conditions. An attacker who exploited the vulnerability could run arbitrary code with medium-integrity level privileges (the permissions of the current user).

In a web-based attack scenario, an attacker could host a website in an attempt to exploit this vulnerability. In addition, compromised websites and websites that accept or host user-provided content could contain specially crafted content that could exploit the vulnerability.

However, in all cases an attacker would have no way to force users to view the attacker-controlled content. Instead, an attacker would have to convince users to take action. For example, an attacker could trick users into clicking a link that takes the user to the attacker's site. The update addresses the vulnerability by fixing how the Internet Explorer XSS Filter validates JavaScript.

The following table contains links to the standard entry for each vulnerability in the Common Vulnerabilities and Exposures list:

Vulnerability title CVE number Publicly disclosed Exploited
Internet Explorer XSS Filter Vulnerability CVE-2016-3212 No No

Mitigating Factors

Microsoft has not identified any mitigating factors for this vulnerability.

Workarounds

Microsoft has not identified any workarounds for this vulnerability.

WPAD Elevation of Privilege Vulnerability - CVE-2016-3213

An elevation of privilege vulnerability exists in Microsoft Windows when the Web Proxy Auto Discovery (WPAD) protocol falls back to a vulnerable proxy discovery process. An attacker who successfully exploited this vulnerability could bypass security and gain elevated privileges on a targeted system.

To exploit the vulnerability, an attacker could respond to NetBIOS name requests for WPAD. The update addresses the vulnerability by correcting how Windows handles proxy discovery.

The following table contains links to the standard entry for each vulnerability in the Common Vulnerabilities and Exposures list:

Vulnerability Title CVE number Publicly disclosed Exploited
WPAD Elevation of Privilege Vulnerability CVE-2016-3213 No No

Mitigating Factors

Microsoft has not identified any mitigating factors for this vulnerability.

Workarounds

The following workarounds may be helpful in your situation.

  • Disable WINS/NetBT name resolution

    1. Open Network Connections.
    2. Click the Local Area Connection to be statically configured, and then from the File menu, click Properties.
    3. In the list of components, click Internet Protocol (TCP/IP), and then click Properties.
    4. Click Advanced, click the WINS tab, and then click Disable NetBIOS over TCP/IP.
      Optionally, you can select the Use NetBIOS setting on the DHCP server if you are using a DHCP server that can selectively enable and disable NetBIOS configuration through DHCP option types.
  • Stop WPAD using a host file entry

    1. Open the host file located at following location as an administrator: %systemdrive%\Windows\System32\Drivers\etc\hosts
    2. Create the following entry for WPAD in the host file: wpad 255.255.255.255

Impact of workaround. Autoproxy discovery will not work, and for this reason, some applications, such as Internet Explorer, will not be able to load websites properly.

How to undo the workaround.

  1. Open the host file located at following location as an administrator: %systemdrive%\Windows\System32\Drivers\etc\hosts
  2. Remove the following entry for WPAD in the host file: wpad 255.255.255.255

Security Update Deployment

For Security Update Deployment information see the Microsoft Knowledge Base article referenced here in the Executive Summary.

Acknowledgments

Microsoft recognizes the efforts of those in the security community who help us protect customers through coordinated vulnerability disclosure. See Acknowledgments for more information.

Disclaimer

The information provided in the Microsoft Knowledge Base is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

Revisions

  • V1.0 (June 14, 2016): Bulletin published.
  • V1.1 (June 22, 2016): Bulletin revised to add workarounds for CVE-2016-3213. This is an informational change only. Customers who have successfully installed the updates do not need to take any further action.

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