CVE-2010-3240 in Office Compatibility Pack
Summary
by MITRE
Microsoft Excel 2002 SP3 and 2007 SP2; Excel Viewer SP2; and Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats SP2 do not properly validate record information, which allows remote attackers to execute arbitrary code via a crafted Excel document, aka "Real Time Data Array Record Vulnerability."
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Analysis
by VulDB Data Team • 09/26/2021
The vulnerability identified as CVE-2010-3240 represents a critical flaw in Microsoft Excel's file parsing mechanism that affects multiple versions including Excel 2002 SP3 and 2007 SP2, Excel Viewer SP2, and the Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats SP2. This vulnerability falls under the category of improper input validation and specifically manifests as a failure in record information validation within Excel's binary file format parser. The flaw enables remote code execution through the manipulation of Real Time Data Array records, which are part of Excel's proprietary file format structure. According to CWE-129, this vulnerability stems from insufficient validation of input data, allowing attackers to craft malicious Excel documents that exploit the parsing logic. The vulnerability is particularly concerning because it operates at the file format level, making it difficult to detect through traditional network-based security measures.
The technical exploitation of this vulnerability occurs when Excel processes a specially crafted document containing malformed Real Time Data Array records. These records are used to store dynamic data connections and real-time data updates within Excel files. When the vulnerable Excel application attempts to parse these malformed records, the improper validation allows an attacker to manipulate memory structures and execute arbitrary code with the privileges of the user running the application. The vulnerability is classified under the ATT&CK technique T1203 - Exploitation for Client Execution, where attackers leverage application vulnerabilities to execute malicious code on targeted systems. The flaw essentially creates a buffer overflow condition or memory corruption scenario that can be leveraged to gain remote code execution capabilities.
The operational impact of CVE-2010-3240 extends beyond simple code execution as it represents a significant threat to enterprise security environments where Excel documents are frequently shared and opened. Organizations using affected versions of Microsoft Office are particularly vulnerable to targeted attacks where malicious documents are distributed through email attachments, file sharing systems, or web downloads. The vulnerability's remote exploitation capability means that attackers do not require physical access to target systems, making it a prime candidate for large-scale automated attacks. Security professionals must consider this vulnerability as part of broader attack surface management, particularly in environments where users frequently open documents from untrusted sources. The vulnerability also impacts the security posture of organizations that rely on Excel for data processing and analysis, as these applications are often used in sensitive business environments.
Mitigation strategies for CVE-2010-3240 should focus on both immediate patching and operational security measures. Microsoft released security updates that address the record validation flaw in affected versions of Excel and related applications. Organizations should prioritize deployment of these patches as a first line of defense, as they directly address the root cause of the vulnerability. Additionally, implementing email filtering and document inspection systems can provide layered protection against malicious Excel documents. According to the ATT&CK framework, defensive measures should include application whitelisting and the restriction of file type execution to prevent unauthorized code from running. Network segmentation and user access controls should be implemented to limit the potential impact of successful exploitation attempts. Security awareness training for end users remains critical, as social engineering attacks often leverage this vulnerability through phishing campaigns that distribute malicious Excel documents. Organizations should also consider implementing sandboxing technologies for document processing and establishing strict policies around document sharing and opening from external sources. The vulnerability highlights the importance of maintaining up-to-date security patches and the need for comprehensive vulnerability management programs that address both known and emerging threats in Microsoft Office applications.