CVE-2010-3238 in Office
Summary
by MITRE
Microsoft Excel 2002 SP3 and 2003 SP3, and Office 2004 for Mac, does not properly validate binary file-format information, which allows remote attackers to execute arbitrary code via a crafted Excel document, aka "Negative Future Function Vulnerability."
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Analysis
by VulDB Data Team • 09/26/2021
The vulnerability identified as CVE-2010-3238 represents a critical security flaw in Microsoft Excel versions 2002 SP3, 2003 SP3, and Office 2004 for Mac that stems from improper validation of binary file-format information. This weakness enables remote attackers to execute arbitrary code through the manipulation of specially crafted Excel documents, making it a significant threat to enterprise security environments where spreadsheet files are frequently exchanged and opened. The vulnerability specifically targets the parsing mechanisms used by these Excel versions when processing binary data structures within spreadsheet files.
The technical flaw manifests in the way Excel handles negative future function references within binary file formats, particularly in the context of structured reference parsing and formula evaluation. When an attacker constructs a malicious Excel document containing malformed binary data with negative future function indicators, the application fails to properly validate these constructs before processing them. This validation failure occurs during the file parsing phase where Excel attempts to interpret complex binary structures, leading to potential memory corruption and code execution. The vulnerability falls under the CWE-125 Out-of-bounds Read category, as the application reads memory locations beyond the intended boundaries during binary format processing, and aligns with CWE-787 Out-of-bounds Write when the corrupted memory is subsequently written to.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with a remote exploitation vector that can be leveraged across various network environments. The attack typically begins with the delivery of a malicious Excel document through phishing emails, compromised websites, or file sharing platforms where users unknowingly open the infected files. Once opened, the malicious code executes with the privileges of the user running Excel, potentially leading to full system compromise, data exfiltration, or establishment of persistent backdoors. This vulnerability is particularly dangerous in enterprise settings where users frequently open spreadsheet files from external sources, making it a prime target for targeted attacks and mass exploitation campaigns.
The exploitation of this vulnerability follows patterns consistent with the attack tactics described in the MITRE ATT&CK framework, specifically mapping to T1203 Exploitation for Client Execution and T1059 Command and Scripting Interpreter. The attack chain typically involves initial access through social engineering, followed by the execution of malicious code within the Excel application context. Organizations should consider implementing multiple layers of defense including email filtering solutions, application whitelisting policies, and regular security updates to mitigate this threat. The vulnerability also highlights the importance of secure coding practices and proper input validation in office productivity applications, as demonstrated by the Common Weakness Enumeration classification that emphasizes the need for bounds checking and proper memory management in binary format parsers.