CVE-2012-2543 in Office Excel
Summary
by MITRE
Stack-based buffer overflow in Microsoft Excel 2007 SP2 and SP3 and 2010 SP1; Office 2011 for Mac; Excel Viewer; and Office Compatibility Pack SP2 and SP3 allows remote attackers to execute arbitrary code via a crafted spreadsheet, aka "Excel Stack Overflow Vulnerability."
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Analysis
by VulDB Data Team • 04/19/2021
The CVE-2012-2543 vulnerability represents a critical stack-based buffer overflow flaw affecting multiple Microsoft Excel versions including 2007 SP2 and SP3, 2010 SP1, Office 2011 for Mac, Excel Viewer, and the Office Compatibility Pack SP2 and SP3. This vulnerability operates through a sophisticated attack vector where remote adversaries can craft malicious spreadsheets designed to exploit the buffer overflow condition during spreadsheet processing. The flaw resides in how Excel handles certain data structures within spreadsheet files, specifically when parsing and rendering complex cell formats or formulas that exceed allocated stack memory boundaries.
The technical implementation of this vulnerability leverages a classic stack overflow exploit pattern where malicious input data causes the program to write beyond the bounds of allocated stack memory regions. When Excel processes a specially crafted spreadsheet containing oversized or malformed data structures, the application fails to properly validate input boundaries, leading to memory corruption that can be manipulated to redirect program execution flow. This type of vulnerability directly maps to CWE-121, which describes stack-based buffer overflow conditions where insufficient boundary checking allows attackers to overwrite adjacent memory locations including return addresses and function parameters.
The operational impact of this vulnerability extends beyond simple code execution as it provides attackers with the capability to gain complete control over affected systems. Attackers can leverage this vulnerability through various delivery mechanisms including email attachments, web downloads, or malicious documents shared through collaboration platforms. The exploit requires no user interaction beyond opening the malicious spreadsheet file, making it particularly dangerous in enterprise environments where users frequently open documents from external sources. The vulnerability affects both Windows and Mac platforms, expanding the potential attack surface significantly.
Security professionals should consider this vulnerability in relation to the broader ATT&CK framework, particularly under the T1059 technique category for command and control through application execution. The exploit chain typically involves initial access through social engineering or compromised websites followed by execution of malicious code within the Excel application context. Organizations should implement multiple layers of defense including email filtering, web application firewalls, and regular patch management processes to mitigate exposure. The vulnerability highlights the importance of maintaining current Office security updates and implementing strict document validation policies. Microsoft released patches for this vulnerability through regular security updates, and administrators should ensure all affected systems receive immediate remediation. Network segmentation and user access controls can help limit potential damage if exploitation occurs, while endpoint detection and response solutions can provide visibility into exploitation attempts. The vulnerability underscores the critical need for continuous security assessment and vulnerability management programs to identify and remediate similar issues before they can be exploited in the wild.