Vulnerabilities in Microsoft Office Could Allow Remote Code Execution (MS15-110)

ITS Advisory Number: 
2015-127
Date(s) Issued: 
Tuesday, October 13, 2015
Subject: 
Vulnerabilities in Microsoft Office Could Allow Remote Code Execution (MS15-110)
Overview: 

Multiple vulnerabilities have been discovered in Microsoft Office that could allow remote code execution. Successful exploitation of these vulnerabilities could result in an attacker gaining the same privileges as the logged on user. Depending on the privileges associated with the user, an attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

Systems Affected: 
  • Microsoft Excel 2007, Microsoft Visio 2007
  • Microsoft Excel 2010, Microsoft Visio 2010
  • Microsoft Excel 2013, Microsoft Excel 2013 RT
  • Microsoft Excel 2016
  • Microsoft Excel for Mac 2011
  • Microsoft Excel 2016 for Mac
  • Microsoft Excel Viewer, Microsoft Office Compatibility Pack
  • Excel Services on Microsoft SharePoint Server 2007
  • Excel Services on Microsoft SharePoint Server 2010, Microsoft Web App 2010, Microsoft Excel Web App 2010
  • Excel Services on Microsoft SharePoint Server 2013, Microsoft Office Web Apps Server 2013
  • Microsoft SharePoint Server 2007
  • Microsoft SharePoint Server 2010
  • Microsoft SharePoint Server 2013, Microsoft SharePoint Foundation 2013
RISK
GOVERNMENT
Large and medium government entities: 
High
Small government entities: 
High
BUSINESS
Large and medium business entities: 
High
Small business entities: 
High
Home Users: 
High
Description: 

Multiple vulnerabilities exist in Microsoft Office software. Details of them are as follows;

  • When the Office software fails to properly handle objects in memory. [CVE-2015-2555], [CVE-2015-2557], [CVE-2015-2558]
  • An information disclosure vulnerability exists when SharePoint InfoPath Forms Services improperly parses the Document Type Definition (DTD) of an XML file. [CVE-2015-2556]
  • A spoofing vulnerability exists when an Office Web Apps Server does not properly sanitize a specially crafted request. [CVE-2015-6037]
  • A security feature bypass vulnerability exists in Microsoft SharePoint. The vulnerability is caused when Office Marketplace is allowed to inject JavaScript code that persists onto a SharePoint page, because SharePoint does not enforce the appropriate permission level for an application or user. [CVE-2015-6039]

Successful exploitation of any of these vulnerabilities could result in an attacker gaining the same privileges as the logged on user. Depending on the privileges associated with the user, 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.

 

Actions: 
  • After appropriate testing, apply appropriate patches provided by Microsoft to vulnerable systems.
  • Run all software as a non-privileged user (one without administrative privileges) to diminish the effects of a successful attack.
  • Remind users not to open files provided by unknown or un-trusted sources.
  • Inform and educate users regarding the threats posed by opening files, especially those from un-trusted sources or suspicious files from trusted sources.