Microsoft Security Bulletin MS15-093 - Critical

• 10/11/2017
• 10 minutes to read
• • 
  • 
  • 

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 

^[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:

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: