Cumulative Security Update for JScript and VBScript to Address Remote Code Execution (3125540)
Published: January 12, 2016 | Updated: May 25, 2016
Version: 1.1
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 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 Vista, Windows Server 2008, and Server Core installations of Windows Server 2008 R2. For more information, see the AffectedSoftware section.
The update addresses the vulnerability by modifying how the VBScript scripting engine handles objects in memory. For more information about the vulnerability, see the VulnerabilityInformation section.
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 3124275 (MS16-001), which also addresses the vulnerability discussed in this bulletin.
*The Updates Replaced column shows only the latest update in any chain of superseded updates.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
Why do I see both JScript.dll and VBScript.dll in the packages for this cumulative security update?
This security update ships as a cumulative update for the JScript and VBScript scripting engines. While both engines are included in this release, the components affected by the security fixes covered by this bulletin are listed above in the section AffectedSoftware.
How do I determine which versions of JScript and VBScript scripting engines are installed on my system?
The JScript and VBScript scripting engines are 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 JScript and VBScript scripting engine that are installed.
To determine which versions of the JScript or VBScript scripting engines are installed on your system, perform the following steps:
Open Windows Explorer.
Navigate to the %systemroot%\system32 directory.
For VBScript, right-click vbscript.dll, select Properties, and then click the Details tab.
For JScript, right-click jscript.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 JScript or VBScript scripting engine installed on my system, where do I get the update?
The affected software in this bulletin apply to systems without Internet Explorer installed and to systems with Internet Explorer 7 or earlier versions installed. Customers with systems running Internet Explorer 8 or later should apply the Internet Explorer Cumulative Update (MS16-001), which also addresses the vulnerability discussed in this bulletin.
The following table summarizes which bulletin provides the update by version of JScript and VBScript, and Internet Explorer.
JScript 5.7 and VBScript 5.7\ (Internet Explorer 7)
JScript 5.7 and VBScript 5.7 \ (3124624)
Not applicable
JScript 5.8 and VBScript 5.8\ (Internet Explorer 8)
JScript 5.8 and VBScript 5.8 \ (3124625)\ (Windows Server Core installation on Windows Server 2008 R2 for x64-based Systems Service Pack 1 only.)
Internet Explorer 8 \ (3124275)
JScript 5.8 and VBScript 5.8\ (Internet Explorer 9)
Not applicable
Internet Explorer 9 \ (3124275)
JScript 5.8 and VBScript 5.8\ (Internet Explorer 10)
Not applicable
Internet Explorer 10 \ (3124275)
JScript 5.8 and VBScript 5.8\ (Internet Explorer 11)
Not applicable
Internet Explorer 11 \ (3124275)
JScript 5.8 and VBScript 5.8\ (Internet Explorer 11)
Not applicable
Internet Explorer 11 on Windows 10\ (3124266)
JScript 5.8 and VBScript 5.8\ (Internet Explorer 11)
Not applicable
Internet Explorer 11 on Windows 10 Version 1511\ (3124263)
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 January bulletin summary.
Vulnerability Severity Rating and Maximum Security Impact by Affected Software
A remote code execution vulnerability exists in the way that the VBScript engine renders when handling objects in memory in Internet Explorer. The vulnerability could corrupt memory in such a way that an attacker could execute arbitrary code in the context of the current user.
In a web-based attack scenario, an attacker could host a specially crafted website that is designed to exploit the 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 the vulnerability.
An attacker who successfully exploited the 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 the vulnerability 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.
The update addresses the vulnerability by modifying how the VBScript scripting engine handles objects in memory.
The following table contains links to the standard entry for each vulnerability in the Common Vulnerabilities and Exposures list:
For Security Update Deployment information, see the Microsoft Knowledge Base article referenced 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 (January 12, 2016): Bulletin published.
V1.1 (May 25, 2016): Removed redundant rows from the Vulnerability Severity Rating and Maximum Security Impact by Affected Software table, and added the applicable update numbers for clarity. This is an informational change only.
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