CVE-2012-1847 in Excel
Summary
by MITRE
Microsoft Excel 2003 SP3, 2007 SP2 and SP3, and 2010 Gold and SP1; Office 2008 and 2011 for Mac; Excel Viewer; and Office Compatibility Pack SP2 and SP3 do not properly handle memory during the opening of files, which allows remote attackers to execute arbitrary code via a crafted spreadsheet, aka "Excel Series Record Parsing Type Mismatch Could Result in Remote Code Execution Vulnerability."
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Analysis
by VulDB Data Team • 03/24/2021
This vulnerability represents a critical memory handling flaw in Microsoft Excel applications that affects multiple versions across different platforms including Windows and Mac operating systems. The vulnerability stems from improper memory management during the parsing of spreadsheet files, specifically when processing the Series record within Excel's file format structure. The flaw occurs when Excel attempts to open maliciously crafted spreadsheet files that contain malformed Series records, leading to a type mismatch condition in memory allocation and handling. This memory corruption vulnerability enables remote attackers to execute arbitrary code on affected systems simply by opening a specially crafted Excel file, making it particularly dangerous for targeted attacks and mass distribution campaigns.
The technical nature of this vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and CWE-787, which covers out-of-bounds writes in buffer operations. The vulnerability operates through a type mismatch parsing scenario where Excel's internal memory management fails to properly validate data types during the Series record processing phase. When a malicious file is opened, the application attempts to allocate memory based on incorrect assumptions about the data structure, leading to memory corruption that can be exploited to overwrite critical memory locations with attacker-controlled code. This type of vulnerability falls under the ATT&CK technique T1203, specifically "Exploitation for Client Execution," as it leverages the Excel application's file opening functionality to achieve remote code execution through malicious file delivery.
The operational impact of this vulnerability extends beyond simple exploitation as it affects a wide range of Microsoft Office products, making it particularly dangerous for enterprise environments where these applications are commonly used. The vulnerability can be triggered through various attack vectors including email attachments, web downloads, and file sharing mechanisms, making it difficult to defend against completely. Organizations using affected versions of Excel are at significant risk of compromise, as the attack requires minimal user interaction beyond opening the malicious file, and the exploitation process can be automated through various attack frameworks. The vulnerability's persistence across multiple Office versions and platforms means that traditional patch management approaches may not be sufficient to address all affected systems, requiring comprehensive vulnerability assessment and remediation efforts.
Mitigation strategies for this vulnerability should include immediate application of Microsoft security patches and updates, which address the underlying memory handling issues in Excel's file parsing routines. Organizations should implement strict email filtering and file validation policies to prevent malicious files from reaching end users, while also considering the deployment of endpoint protection solutions that can detect and block exploitation attempts. Network segmentation and access controls should be strengthened to limit the potential impact of successful exploitation, and regular security awareness training should be conducted to educate users about the risks of opening untrusted Excel files. Additionally, implementing application whitelisting policies that restrict the execution of unauthorized applications can provide an additional layer of protection against exploitation attempts. The vulnerability serves as a reminder of the critical importance of maintaining up-to-date security patches and implementing layered security approaches to protect against sophisticated exploitation techniques targeting common productivity applications.