Rule Category

FILE-OFFICE -- Snort detected traffic targeting vulnerabilities in files belonging to the Microsoft Office suite of software (Excel, PowerPoint, Word, Visio, Access, Outlook, etc.).

Alert Message

FILE-OFFICE Microsoft Office Excel conditional code execution attempt

Rule Explanation

Microsoft Excel 2003 SP3 and 2007 SP2; Excel in Office 2007 SP2; Excel 2010 Gold and SP1; Excel in Office 2010 Gold and SP1; Office 2004, 2008, and 2011 for Mac; Open XML File Format Converter for Mac; Excel Viewer SP2; Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats SP2; Excel Services on Office SharePoint Server 2007 SP2; Excel Services on Office SharePoint Server 2010 Gold and SP1; and Excel Web App 2010 Gold and SP1 do not properly parse conditional expressions associated with formatting requirements, which allows remote attackers to execute arbitrary code via a crafted spreadsheet, aka "Excel Conditional Expression Parsing Vulnerability." Impact: CVSS base score 9.3 CVSS impact score 10.0 CVSS exploitability score 8.6 confidentialityImpact COMPLETE integrityImpact COMPLETE availabilityImpact COMPLETE Details: Ease of Attack:

What To Look For

Known Usage

No public information

False Positives

No known false positives

Contributors

Talos research team. This document was generated from data supplied by the national vulnerability database, a product of the national institute of standards and technology. For more information see [nvd].

MITRE ATT&CK Framework

Tactic:

Technique:

For reference, see the MITRE ATT&CK vulnerability types here: https://attack.mitre.org

CVE

Additional Links

Rule Vulnerability

CVE Additional Information

CVE-2011-1989
Microsoft Excel 2003 SP3 and 2007 SP2; Excel in Office 2007 SP2; Excel 2010 Gold and SP1; Excel in Office 2010 Gold and SP1; Office 2004, 2008, and 2011 for Mac; Open XML File Format Converter for Mac; Excel Viewer SP2; Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats SP2; Excel Services on Office SharePoint Server 2007 SP2; Excel Services on Office SharePoint Server 2010 Gold and SP1; and Excel Web App 2010 Gold and SP1 do not properly parse conditional expressions associated with formatting requirements, which allows remote attackers to execute arbitrary code via a crafted spreadsheet, aka "Excel Conditional Expression Parsing Vulnerability."
Details
SeverityHIGH Base Score9.3
Impact Score10.0 Exploit Score8.6
Confidentiality ImpactCOMPLETE Integrity ImpactCOMPLETE
Availability ImpactCOMPLETE Access Vector
AuthenticationNONE Ease of Access