Microsoft Security Bulletin MS15-093 - Critical

Security Update for Internet Explorer (3088903)

Published: August 18, 2015 | Updated: August 20, 2015

Version: 1.1

Executive Summary

This security update resolves a vulnerability in Internet Explorer. The vulnerability could allow remote code execution if a user views a specially crafted webpage using Internet Explorer. An attacker who successfully exploited this vulnerability could gain the same user rights as the current user. Customers whose accounts are configured to have fewer user rights on the system could be less impacted than those who operate with administrative user rights.

This security update is rated Critical for Internet Explorer 7 (IE 7), Internet Explorer 8 (IE 8), Internet Explorer 9 (IE 9), Internet Explorer 10 (IE 10), and Internet Explorer 11 (IE 11) on affected Windows clients, and Moderate for Internet Explorer 7 (IE 7), Internet Explorer 8 (IE 8), 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 security update addresses the vulnerability by modifying how Internet Explorer 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 3088903.

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.

Affected Software

Operating System Component Maximum Security Impact Aggregate Severity Rating Updates Replaced
Internet Explorer 7
Windows Vista Service Pack 2 Internet Explorer 7
(3087985)
Remote Code Execution Critical None
Windows Vista x64 Edition Service Pack 2 Internet Explorer 7
(3087985)
Remote Code Execution Critical None
Windows Server 2008 for 32-bit Systems Service Pack 2 Internet Explorer 7
(3087985)
Remote Code Execution Moderate None
Windows Server 2008 for x64-based Systems Service Pack 2 Internet Explorer 7
(3087985)
Remote Code Execution Moderate None
Windows Server 2008 for Itanium-based Systems Service Pack 2 Internet Explorer 7
(3087985)
Remote Code Execution Moderate None
Internet Explorer 8
Windows Vista Service Pack 2 Internet Explorer 8
(3087985)
Remote Code Execution Critical None
Windows Vista x64 Edition Service Pack 2 Internet Explorer 8
(3087985)
Remote Code Execution Critical None
Windows Server 2008 for 32-bit Systems Service Pack 2 Internet Explorer 8
(3087985)
Remote Code Execution Moderate None
Windows Server 2008 for x64-based Systems Service Pack 2 Internet Explorer 8
(3087985)
Remote Code Execution Moderate None
Windows 7 for 32-bit Systems Service Pack 1 Internet Explorer 8
(3087985)
Remote Code Execution Critical None
Windows 7 for x64-based Systems Service Pack 1 Internet Explorer 8
(3087985)
Remote Code Execution Critical None
Windows Server 2008 R2 for x64-based Systems Service Pack 1 Internet Explorer 8
(3087985)
Remote Code Execution Moderate None
Windows Server 2008 R2 for Itanium-based Systems Service Pack 1 Internet Explorer 8
(3087985)
Remote Code Execution Moderate None
Internet Explorer 9
Windows Vista Service Pack 2 Internet Explorer 9
(3087985)
Remote Code Execution Critical None
Windows Vista x64 Edition Service Pack 2 Internet Explorer 9
(3087985)
Remote Code Execution Critical None
Windows Server 2008 for 32-bit Systems Service Pack 2 Internet Explorer 9
(3087985)
Remote Code Execution Moderate None
Windows Server 2008 for x64-based Systems Service Pack 2 Internet Explorer 9
(3087985)
Remote Code Execution Moderate None
Windows 7 for 32-bit Systems Service Pack 1 Internet Explorer 9
(3087985)
Remote Code Execution Critical None
Windows 7 for x64-based Systems Service Pack 1 Internet Explorer 9
(3087985)
Remote Code Execution Critical None
Windows Server 2008 R2 for x64-based Systems Service Pack 1 Internet Explorer 9
(3087985)
Remote Code Execution Moderate None
Internet Explorer 10
Windows 7 for 32-bit Systems Service Pack 1 Internet Explorer 10
(3087985)
Remote Code Execution Critical None
Windows 7 for x64-based Systems Service Pack 1 Internet Explorer 10
(3087985)
Remote Code Execution Critical None
Windows Server 2008 R2 for x64-based Systems Service Pack 1 Internet Explorer 10
(3087985)
Remote Code Execution Moderate None
Windows 8 for 32-bit Systems Internet Explorer 10
(3087985)
Remote Code Execution Critical None
Windows 8 for x64-based Systems Internet Explorer 10
(3087985)
Remote Code Execution Critical None
Windows Server 2012 Internet Explorer 10
(3087985)
Remote Code Execution Moderate None
Windows RT Internet Explorer 10[1] (3087985) Remote Code Execution Critical None
Internet Explorer 11
Windows 7 for 32-bit Systems Service Pack 1 Internet Explorer 11
(3087985)
Remote Code Execution Critical None
Windows 7 for x64-based Systems Service Pack 1 Internet Explorer 11
(3087985)
Remote Code Execution Critical None
Windows Server 2008 R2 for x64-based Systems Service Pack 1 Internet Explorer 11
(3087985)
Remote Code Execution Moderate None
Windows 8.1 for 32-bit Systems Internet Explorer 11
(3087985)
Remote Code Execution Critical None
Windows 8.1 for x64-based Systems Internet Explorer 11
(3087985)
Remote Code Execution Critical None
Windows Server 2012 R2 Internet Explorer 11
(3087985)
Remote Code Execution Moderate None
Windows RT 8.1 Internet Explorer 11[1] (3087985) Remote Code Execution Critical None
Windows 10 for 32-bit Systems[2] (3081444) Internet Explorer 11 Remote Code Execution Critical 3081436 in MS15-079
Windows 10 for x64-based Systems[2] (3081444) Internet Explorer 11 Remote Code Execution Critical 3081436 in MS15-079

[1]This update is available via Windows Update.

[2]The Windows 10 update is cumulative. In addition to containing non-security updates, it also contains all of the security fixes for all of the Windows 10-affected vulnerabilities shipping with this month’s security release. See Microsoft Knowledge Base Article 3081444 for more information and download links.

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

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 August 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 7 Internet Explorer 8 Internet Explorer 9 Internet Explorer 10 Internet Explorer 11 Internet Explorer 11

on Windows 10

CVE-2015-2502 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
Windows Clients:
Critical / RCE
Windows Servers:
Moderate / RCE
Windows Clients:
Critical / RCE

Update FAQ

Is update 3081444 a cumulative security update for Internet Explorer 11?
Yes. Security update 3081444 is a cumulative security update for users running Internet Explorer 11 on Windows 10.

Is update 3087985 a cumulative security update for Internet Explorer?
No. Security update 3087985 is not a cumulative update.

Are there any prerequisites for update 3087985?
Yes. Customers running Internet Explorer 7, Internet Explorer 8, Internet Explorer 9, Internet Explorer 10, or Internet Explorer 11 on Windows 7, Windows Server 2008 R2, Windows 8.1, Windows Server 2012 R2, or Windows RT 8.1 must first install the 3078071 update released on August 11, 2015 before installing the 3087985 update.

Note For Download Center customers:

If you download and install updates manually, you must first install update 3078071 before installing update 3087985. Failure to follow the install order can lead to degraded functionality.

Vulnerability Information

Memory Corruption Vulnerability – CVE-2015-2502

A remote code execution vulnerability exists when Internet Explorer improperly accesses objects in memory. This vulnerability could corrupt memory in such a way that an attacker could execute arbitrary code in the context of the current user.

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. The attacker could also take advantage of compromised websites and websites that accept or host user-provided content or advertisements by adding specially crafted content that could exploit this vulnerability. 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 getting them to click a link in an instant messenger or email message that takes users to the attacker's website, or by getting them to open an attachment sent through email.

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. Systems where Internet Explorer is used frequently, such as workstations or terminal servers, are at the most risk from this vulnerability.

The update addresses the vulnerability 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
Memory Corruption Vulnerability CVE-2015-2502 No Yes

Mitigating Factors

Microsoft has not identified any mitigating factors for the vulnerability.

Workarounds

Microsoft has not identified any workarounds for the 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 2003, 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.

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 (August 18, 2015): Bulletin published.
  • V1.1 (August 20, 2015): Bulletin revised to announce a detection change in the 3087985 update for Internet Explorer. This is a detection change only. Customers who have already successfully updated their systems do not need to take any action.

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