Vulnerabilities in Microsoft Excel Could Allow Remote Code Execution (2858300)
Executive Summary
This security update resolves three privately reported vulnerabilities in Microsoft Office. The most severe vulnerabilities could allow remote code execution if a user opens a specially crafted Office file with an affected version of Microsoft Excel or other affected Microsoft Office software. An attacker who successfully exploited the most severe vulnerabilities could gain the same user rights as the current user. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.
This security update is rated Important for all supported editions of Microsoft Excel 2003, Microsoft Excel 2007, Microsoft Excel 2010, Microsoft Excel 2013, Microsoft Excel 2013 RT, and Microsoft Office for Mac 2011; it is also rated Important for supported versions of Microsoft Excel Viewer and Microsoft Office Compatibility Pack. For more information, see the subsection, Affected and Non-Affected Software, in this section.
The security update addresses the vulnerabilities by correcting how Microsoft Excel and other affected Microsoft software validates data when parsing specially crafted Office files and by correcting the manner in which the XML parser used by Excel resolves external entities within a specially crafted file. For more information about the vulnerabilities, see the Frequently Asked Questions (FAQ) subsection for the specific vulnerability entry under the next section, Vulnerability Information.
Recommendation. Customers can configure automatic updating to check online for updates from Microsoft Update by using the Microsoft Update service. Customers who have automatic updating enabled and configured to check online for updates from Microsoft Update typically will not need to take any action because this security update will be downloaded and installed automatically. Customers who have not enabled automatic updating need to check for updates from Microsoft Update and install this update manually. For information about specific configuration options in automatic updating, see Microsoft Knowledge Base Article 294871.
For administrators and enterprise installations, or end users who want to install this security update manually, Microsoft recommends that customers apply the update at the earliest opportunity using update management software, or by checking for updates using the Microsoft Update service.
For customers of Microsoft Office for Mac, Microsoft AutoUpdate for Mac can be configured to deliver updates for Microsoft software directly to your system. For more information, seeCheck for Office for Mac updates automatically.