PT-2013-72: XML External Entities Resolution vulnerability in Microsoft Office Excel Vulnerable softwareMicrosoft Office Excel Version: 2010 SP2 and earlier; 2007 SP3 and earlier; 2003 SP3 and earlierMicrosoft Excel Viewer Version: 2007 SP3 and earlierLink: http://microsoft.com/Severity levelSeverity level: Medium Impact: Internal Network Resources and File System Access, Denial of Service Access Vector: Remote CVSS v2: Base Score: 5.8 Vector: (AV:N/AC:M/Au:N/C:P/I:N/A:P)CVE: CVE-2013-3159Software descriptionMicrosoft Office Excel is a commercial spreadsheet application written and distributed by Microsoft for Microsoft Windows and Mac OS X. Vulnerability descriptionThe specialists of the Positive Research center have detected an XML External Entities Resolution vulnerability in Microsoft Office Excel.The vulnerability is possible due to unsafe parsing of XML external entities. If an attacker makes a victim open a specially crafted XML document, Microsoft Office Excel installed on the vistim's system will automatically send the contents of local or remote resource to the attacker's server. It also makes possible to conduct denial of service attacks.How to fixUse vendor's advisory: http://technet.microsoft.com/en-us/security/bulletin/ms13-073Advisory status 26.11.2012 - Vendor gets vulnerability details 10.09.2013 - Vendor releases fixed version and details 09.10.2013 - Public disclosureCreditsThe vulnerability was detected by Timur Yunusov, Alexey Osipov and Ilya Karpov, Positive Research Center (Positive Technologies Company)Referenceshttp://en.securitylab.ru/lab/PT-2013-72 Reports on the vulnerabilities previously discovered by Positive Research:http://www.ptsecurity.com/research/advisory/ http://en.securitylab.ru/lab/
