Microsoft Excel MDXSET Record Heap Overflow Vulnerability
Excel is the spreadsheet application included with Microsoft Corp.'s Office productivity software suite. More information is available at the following website:
Remote exploitation of a heap overflow vulnerability in Microsoft Corp.'s Excel could allow an attacker to execute arbitrary code with the privileges of the current user.
This vulnerability occurs when parsing an MDXSET record inside of the Excel Workbook globals stream. This record is used to store metadata for external data connections in the workbook. The vulnerability occurs when a MDXSET record is broken up into several records. This could allow an attacker to trigger a heap based buffer overflow by controling both the allocation size of a heap buffer and the number of bytes copied into this buffer.
Exploitation of this vulnerability results in the execution of arbitrary code with the privileges of the user opening the file. To exploit this vulnerability, an attacker needs to convince a user to open a malicious file. Attackers typically accomplish this by emailing a targeted user the file, or hosting the file on a Web page.
Exploitation of this vulnerability is relatively simple. An attacker can control the size of the buffer allocated, the size of the overflow, and the content of the overflow.
iDefense has confirmed the existence of this vulnerability in Excel versions 2007 SP0, SP1, and SP2. Previous versions do not appear to be affected as they do not support parsing the record that triggers the vulnerability. A full list of vulnerable Microsoft products can be found in Microsoft Security Bulletin MS10-017.
Microsoft suggested workarounds can be found in Microsoft Security Bulletin MS10-017.
Microsoft Corp. has released a patch which addresses this issue. Information about downloadable vendor updates can be found by clicking on the URLs shown. http://www.microsoft.com/technet/security/bulletin/MS10-017.mspx
The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2010-0261 to this issue. This is a candidate for inclusion in the CVE list (http://cve.mitre.org/), which standardizes names for security problems.
09/25/2009 Initial Vendor Notification
09/25/2009 Initial Vendor Reply
03/09/2010 Coordinated Public Disclosure
This vulnerability was discovered by Sean Larsson, iDefense Labs.
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