Microsoft Security Bulletin MS15-066 - Critical

Vulnerability in VBScript Scripting Engine Could Allow Remote Code Execution (3072604)

Published: July 14, 2015

Version: 1.0

Executive Summary

This security update resolves a vulnerability in the VBScript scripting engine in Microsoft Windows. The vulnerability could allow remote code execution if a user visits a specially crafted website. An attacker who successfully exploited this vulnerability 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 this vulnerability could take complete 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 affected versions of the VBScript scripting engine on supported editions of Windows Server 2003, Windows Vista, Windows Server 2008, and Server Core installations of Windows Server 2008 R2. For more information, see the Affected Software section.

The security update addresses the vulnerability by modifying how the VBScript scripting engine handles objects in memory. For more information about the vulnerability, see the Vulnerability Information section.

For more information about this update, see Microsoft Knowledge Base Article 3072604.

Affected Software

The following versions of VBScript are affected by the vulnerability discussed in this bulletin. Earlier versions or editions that are not listed are either past their support life cycle or are not affected. The following affected software apply to systems with Internet Explorer 7 or earlier installed and to systems without Internet Explorer installed. Customers with systems running Internet Explorer 8 or later should apply Internet Explorer Cumulative Update 3065822 (MS15-065), which also addresses the vulnerability discussed in this bulletin.

Affected Software

Operating System Component Maximum Security Impact Aggregate Severity Rating Updates Replaced*
Windows Server 2003
Windows Server 2003 Service Pack 2 VBScript 5.6
(3068404)
Remote Code Execution Critical 3030403 in MS15-019
Windows Server 2003 Service Pack 2 VBScript 5.7
(3068368)
Remote Code Execution Critical 3030398 in MS15-019
Windows Server 2003 x64 Edition Service Pack 2 VBScript 5.6
(3068404)
Remote Code Execution Critical 3030403 in MS15-019
Windows Server 2003 x64 Edition Service Pack 2 VBScript 5.7
(3068368)
Remote Code Execution Critical 3030398 in MS15-019
Windows Server 2003 with SP2 for Itanium-based Systems VBScript 5.6
(3068404)
Remote Code Execution Critical 3030403 in MS15-019
Windows Server 2003 with SP2 for Itanium-based Systems VBScript 5.7
(3068368)
Remote Code Execution Critical 3030398 in MS15-019
Windows Vista
Windows Vista Service Pack 2 VBScript 5.7
(3068368)
Remote Code Execution Critical 3030398 in MS15-019
Windows Vista x64 Edition Service Pack 2 VBScript 5.7
(3068368)
Remote Code Execution Critical 3030398 in MS15-019
Windows Server 2008
Windows Server 2008 for 32-bit Systems Service Pack 2 VBScript 5.7
(3068368)
Remote Code Execution Critical 3030398 in MS15-019
Windows Server 2008 for x64-based Systems Service Pack 2 VBScript 5.7
(3068368)
Remote Code Execution Critical 3030398 in MS15-019
Windows Server 2008 for Itanium-based Systems Service Pack 2 VBScript 5.7
(3068368)
Remote Code Execution Critical 3030398 in MS15-019
Server Core installation
Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation) VBScript 5.7
(3068368)
Remote Code Execution No severity rating 3030398 in MS15-019
Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation) VBScript 5.7
(3068368)
Remote Code Execution No severity rating 3030398 in MS15-019
Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation) VBScript 5.8
(3068364)
Remote Code Execution No severity rating 3030630 in MS15-019

*The Updates Replaced column shows only the latest update in a 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 on the Package Details tab).

Update FAQ

How do I determine which version of the VBScript scripting engine is installed on my system?
The VBScript scripting engine is installed with supported releases of Microsoft Windows. In addition, installing a newer version of Internet Explorer on a system can change the version of the VBScript scripting engine that is installed.

To determine which version of the VBScript scripting engine is installed on your system, perform the following steps:

  1. Open Windows Explorer.
  2. Navigate to the %systemroot%\system32 directory.
  3. Right-click vbscript.dll, select Properties, and then click the Details tab.

The version number is listed in the File Version field. If your file version starts with 5.8, for example 5.8.7600.16385, then VBScript 5.8 is installed on your system.

Once I know the version of the VBScript scripting engine installed on my system, where do I get the update?
The affected software in this bulletin applies to systems without Internet Explorer installed and to systems with Internet Explorer 8 or earlier versions installed. Customers with systems running Internet Explorer 9 or later should apply the Internet Explorer Cumulative Update (MS15-065), which also addresses the vulnerability discussed in this bulletin.

The following table summarizes which bulletin provides the update by version of VBScript and Internet Explorer.

Version MS15-066 MS15-065
VBScript 5.6
(Internet Explorer 6)
VBScript 5.6
(3068404)
Not applicable
VBScript 5.7
(Internet Explorer 6 and Internet Explorer 7)
VBScript 5.7
(3068368)
Not applicable
VBScript 5.8
(Internet Explorer 8)
VBScript 5.8
(3068364)
(Windows Server core installation on Windows Server 2008 R2 only)
Internet Explorer 8
(3065822)
VBScript 5.8
(Internet Explorer 9)
Not applicable Internet Explorer 9
(3065822)
VBScript 5.8
(Internet Explorer 10)
Not applicable Internet Explorer 10
(3065822)
VBScript 5.8
(Internet Explorer 11)
Not applicable Internet Explorer 11
(3065822)

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 July bulletin summary.

Vulnerability Severity Rating and Maximum Security Impact by Affected Software
Affected Software VBScript Memory Corruption Vulnerability - CVE-2015-2372 Aggregate Severity Rating
VBScript 5.6 (Internet Explorer 6)
VBScript 5.6 on Windows Server 2003 Service Pack 2
(3068404)
Critical Remote Code Execution Critical
VBScript 5.6 on Windows Server 2003 x64 Edition Service Pack 2
(3068404)
Critical Remote Code Execution Critical
VBScript 5.6 on Windows Server 2003 with SP2 for Itanium-based Systems
(3068404)
Critical Remote Code Execution Critical
VBScript 5.7 (Internet Explorer 7)
VBScript 5.7 on Windows Server 2003 Service Pack 2
(3068368)
Critical Remote Code Execution Critical
VBScript 5.7 on Windows Server 2003 x64 Edition Service Pack 2
(3068368)
Critical Remote Code Execution Critical
VBScript 5.7 on Windows Server 2003 with SP2 for Itanium-based Systems
(3068368)
Critical Remote Code Execution Critical
VBScript 5.7 on Windows Vista Service Pack 2
(3068368)
Critical Remote Code Execution Critical
VBScript 5.7 on Windows Vista x64 Edition Service Pack 2
(3068368)
Critical Remote Code Execution Critical
VBScript 5.7 on Windows Server 2008 for 32-bit Systems Service Pack 2
(3068368)
Critical Remote Code Execution Critical
VBScript 5.7 on Windows Server 2008 for 32-bit Systems Service Pack 2
(Server Core installation)
(3068368)
None
No severity rating
None
VBScript 5.7 on Windows Server 2008 for x64-based Systems Service Pack 2
(3068368)
Critical Remote Code Execution Critical
VBScript 5.7 on Windows Server 2008 for x64-based Systems Service Pack 2
(Server Core installation)
(3068368)
None
No severity rating
None
VBScript 5.7 on Windows Server 2008 for Itanium-based Systems Service Pack 2
(3068368)
Critical Remote Code Execution Critical
VBScript 5.8 (Internet Explorer 8)
VBScript 5.8 on Windows Server 2008 R2 for x64-based Systems Service Pack 1
(Server Core installation)
(3068364)
None
No severity rating
None

Vulnerability Information

VBScript Memory Corruption Vulnerability - CVE-2015-2372

A remote code execution vulnerability exists in the way that the VBScript engine, when rendered in Internet Explorer, handles objects in memory. In a web-based attack scenario, an attacker could host a specially crafted website that is designed to exploit this vulnerability 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 this vulnerability.

An attacker who successfully exploited this vulnerability 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 this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. The update addresses the vulnerability by modifying how the VBScript scripting engine handles objects in memory.

Microsoft received information about this vulnerability through coordinated vulnerability disclosure. When this security bulletin was originally issued, Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers.

Mitigating Factors

Microsoft has not identified any mitigating factors for this vulnerability.

Workarounds

The following workarounds may be helpful in your situation:

  • Restrict access to VBScript.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
      
    • 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
      

    Impact of Workaround. Websites that use VBScript 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
      
    • For 64-bit systems, enter the following command at an administrative command prompt:

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

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 (July 14, 2015): Bulletin published.

Page generated 2015-07-10 13:25Z-07:00.