Microsoft Excel is the spreadsheet application within Microsoft Office.
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. The vulnerability is a logic error that leads to a heap overflow. The exact cause of the vulnerability is a logic error when handling flag values in the SERIES record. This logic error results in a pointer being interpreted incorrectly, which can lead to a heap overflow.
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 e-mailing a targeted user the file or hosting the file on a Web page. Note that attackers cannot exploit Office file format vulnerabilities in a drive-by manner; at the minimum a targeted user has to click an 'open' dialog or choose to view an attachment.
The following Microsoft products are vulnerable:
The vulnerability occurs in the core parsing code of Excel and this code cannot be disabled; however, it is possible to disable the opening of the older binary format files and use MOICE to convert the file to the newer XML-based format. Information about these workarounds is available in the Microsoft bulletin below.
Microsoft Corp. has addressed this vulnerability with the release of updates to Excel. More information can be found at the following URL:
The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2012-1847 to this issue. This is a candidate for inclusion in the CVE list (http://cve.mitre.org/), which standardizes names for security problems.
12/21/2011 Initial Vendor Notification
12/21/2011 Initial Vendor Reply
05/08/2012 Coordinated Public Disclosure
Sean Larsson and Jun Mao of iDefense Labs reported this vulnerability.
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Copyright © 2012 Verisign, Inc.
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