Vulnerabilities in Microsoft Excel Could Allow Remote Code Execution (3017347)
Published: December 9, 2014 | Updated: February 10, 2015
Version: 2.0
Executive Summary
This security update resolves two privately reported vulnerabilities in Microsoft Excel. The vulnerabilities could allow remote code execution if an attacker convinces a user to open or preview a specially crafted Microsoft Excel file in an affected version of Microsoft Office software. An attacker who successfully exploited the vulnerabilities could gain the same user rights as the current user. If the current user is logged on with administrative user rights, an attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Customers 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 2007, Microsoft Excel 2010, Microsoft Excel 2013, Microsoft Excel 2013 RT, Microsoft Office Excel Viewer, and Microsoft Office Compatibility Pack. For more information, see the Affected Software section.
The security update addresses the vulnerabilities by correcting how Microsoft Excel parses specially crafted Office files. For more information about the vulnerabilities, see the Vulnerability Information section for the specific vulnerability.
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.
[2]This update also addresses a vulnerability discussed in MS15-012, which is being released concurrently with this rerelease. Note that the fixes for the vulnerabilities in both bulletins are contained in a single update package.
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 December bulletin summary.
Vulnerability Severity Rating and Maximum Security Impact by Affected Software
Microsoft Excel 2010 Service Pack 2 (32-bit editions)
Important \ Remote Code Execution
Important \ Remote Code Execution
Important
Microsoft Excel 2010 Service Pack 2 (64-bit editions)
Important \ Remote Code Execution
Important \ Remote Code Execution
Important
Microsoft Excel 2013 and Microsoft Excel 2013 RT
Microsoft Excel 2013 (32-bit editions)
Not applicable
Important \ Remote Code Execution
Important
Microsoft Excel 2013 Service Pack 1 (32-bit editions)
Not applicable
Important \ Remote Code Execution
Important
Microsoft Excel 2013 (64-bit editions)
Not applicable
Important\ Remote Code Execution
Important
Microsoft Excel 2013 Service Pack 1 (64-bit editions)
Not applicable
Important\ Remote Code Execution
Important
Microsoft Excel 2013 RT
Not applicable
Important\ Remote Code Execution
Important
Microsoft Excel 2013 RT Service Pack 1
Not applicable
Important \ Remote Code Execution
Important
Other Office Software
Microsoft Excel Viewer
Important \ Remote Code Execution
Not applicable
Important
Microsoft Office Compatibility Pack
Important Remote Code Execution
Important Remote Code Execution
Important
Vulnerability Information
Global Free Remote Code Execution in Excel Vulnerability - CVE-2014-6360
A remote code execution vulnerability exists in how Microsoft Excel improperly handles objects in memory while parsing specially crafted Office files. System memory may be corrupted in such a way that an attacker could execute arbitrary code. An attacker who successfully exploited this vulnerability could run arbitrary code in the context of the current user. If the current user is logged on with administrative user rights, an attacker could take complete control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. 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.
Systems where affected Microsoft Excel software is used, including workstations and terminal servers, are primarily at risk. Servers could be at more risk if administrators allow users to log on to servers and to run programs. However, best practices strongly discourage allowing this. Exploitation of this vulnerability requires that a user open a specially crafted file with an affected version of Microsoft Office software.
In an email attack scenario, an attacker could exploit the vulnerability by sending a specially crafted file to the user and by convincing the user to open the file in an affected version of Microsoft Office software. In a web-based attack scenario, an attacker could host a website that contains a file that is used to attempt to exploit the vulnerability. In addition, compromised websites and websites that accept or host user-provided content could contain specially crafted content that could exploit this vulnerability. An attacker would have no way to force users to visit a specially crafted website. Instead, an attacker would have to convince them to visit the website, typically by getting them to click a link in an email message or Instant Messenger message that takes them to the attacker's site, and then convince them to open the specially crafted file in an affected version of Microsoft Office software.
This update addresses the vulnerability by correcting how Microsoft Excel parses specially crafted files. Microsoft received information about this vulnerability through coordinated vulnerability disclosure. When this security bulletin was issued, Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers.
An attacker who successfully exploited this vulnerability could run arbitrary code in the context of 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.
The vulnerability cannot be exploited automatically through email. For an attack to be successful a user must open an attachment that is sent in an email message.
In a web-based attack scenario, an attacker could host a website that contains a file that is used to attempt to exploit the vulnerability. In addition, compromised websites and websites that accept or host user-provided content could contain specially crafted content that could exploit this vulnerability. An attacker would have no way to force users to visit a specially crafted website. Instead, an attacker would have to convince them to visit the website, typically by getting them to click a link in an email message or Instant Messenger message that takes them to the attacker's site, and then convince them to open the specially crafted file in an affected version of Microsoft Office software.
Workarounds
Microsoft has not identified any workarounds for this vulnerability.
A remote code execution vulnerability exists in how Microsoft Excel improperly handles objects in memory while parsing specially crafted Office files. System memory may be corrupted in such a way that an attacker could execute arbitrary code. An attacker who successfully exploited this vulnerability could run arbitrary code in the context of the current user. If the current user is logged on with administrative user rights, an attacker could take complete control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. 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. Microsoft received information about this vulnerability through coordinated vulnerability disclosure. When this security bulletin was issued, Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers.
Systems where affected Microsoft Excel software is used, including workstations and terminal servers, are primarily at risk. Servers could be at more risk if administrators allow users to log on to servers and to run programs. However, best practices strongly discourage allowing this. Exploitation of this vulnerability requires that a user open a specially crafted file with an affected version of Microsoft Office software.
In an email attack scenario, an attacker could exploit the vulnerability by sending a specially crafted file to the user and by convincing the user to open the file in an affected version of Microsoft Office software. In a web-based attack scenario, an attacker could host a website that contains a file that is used to attempt to exploit the vulnerability. In addition, compromised websites and websites that accept or host user-provided content could contain specially crafted content that could exploit this vulnerability. An attacker would have no way to force users to visit a specially crafted website. Instead, an attacker would have to convince them to visit the website, typically by getting them to click a link in an email message or Instant Messenger message that takes them to the attacker's site, and then convince them to open the specially crafted file in an affected version of Microsoft Office software.
This update addresses the vulnerability by correcting how Microsoft Excel parses specially crafted files. Microsoft received information about this vulnerability through coordinated vulnerability disclosure. When this security bulletin was issued, Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers.
An attacker who successfully exploited this vulnerability could run arbitrary code in the context of 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.
The vulnerability cannot be exploited automatically through email. For an attack to be successful a user must open an attachment that is sent in an email message.
In a web-based attack scenario, an attacker could host a website that contains a file that is used to attempt to exploit the vulnerability. In addition, compromised websites and websites that accept or host user-provided content could contain specially crafted content that could exploit this vulnerability. An attacker would have no way to force users to visit a specially crafted website. Instead, an attacker would have to convince them to visit the website, typically by getting them to click a link in an email message or Instant Messenger message that takes them to the attacker's site, and then convince them to open the specially crafted file in an affected version of Microsoft Office software.
Workarounds
Microsoft has not identified any workarounds for this vulnerability.
Security Update Deployment
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 (December 9, 2014): Bulletin published.
V2.0 (February 10, 2015): Bulletin rereleased to announce the availability of an additional update package for Microsoft Excel Viewer (2920791) that addresses the vulnerabilities discussed in this bulletin. Note that the 2920791 update also addresses a vulnerability discussed in MS15-012, which is being released concurrently. Microsoft recommends that customers running Microsoft Excel Viewer apply the 2920791 update at their earliest convenience. See the Affected Software table for the download link.