CVE-2007-1203 in Excel
Summary
by MITRE
Unspecified vulnerability in Microsoft Excel 2000 SP3, 2002 SP3, 2003 SP2, 2003 Viewer, 2004 for Mac, and 2007 allows user-assisted remote attackers to execute arbitrary code via a crafted set font value in an Excel file, which results in memory corruption.
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Analysis
by VulDB Data Team • 07/18/2019
This vulnerability resides within Microsoft Excel software across multiple versions including Excel 2000 SP3, 2002 SP3, 2003 SP2, 2003 Viewer, 2004 for Mac, and 2007. The flaw manifests when processing a specially crafted font value within an Excel file, creating a memory corruption condition that can be exploited by remote attackers with user assistance. The vulnerability represents a classic buffer overflow scenario where improper input validation leads to unauthorized code execution. This type of vulnerability falls under CWE-121, which describes heap-based buffer overflow conditions, and aligns with ATT&CK technique T1059.005 for command and scripting interpreter execution. The memory corruption occurs during the font processing routine where Excel fails to properly validate font attributes, particularly when handling malformed or oversized font specifications in spreadsheet files.
The exploitation mechanism relies on a user opening a maliciously crafted Excel file containing specially designed font data. When Excel processes this malformed font value, it attempts to allocate memory for the font properties without adequate bounds checking, leading to memory corruption that can be leveraged to execute arbitrary code. The user-assisted nature of this attack means that the victim must actively open the malicious file, but once opened, the attacker can potentially gain full system control. This vulnerability affects the core spreadsheet rendering engine and demonstrates how font handling routines can become attack vectors in office productivity software. The impact extends beyond simple code execution to potential privilege escalation and system compromise, particularly when Excel runs with elevated privileges. The vulnerability's presence across multiple Excel versions indicates a persistent flaw in the font processing code that was not adequately addressed through various service pack updates.
Organizations should implement immediate mitigation strategies including deploying Microsoft security updates and patches as soon as they become available. Network segmentation and email filtering should be enhanced to prevent delivery of potentially malicious Excel files. Users should be trained to avoid opening suspicious files from untrusted sources and to maintain current antivirus signatures. System hardening measures such as disabling automatic file execution and implementing application whitelisting can significantly reduce exploitation risk. The vulnerability highlights the importance of proper input validation in office applications and demonstrates how seemingly innocuous features like font handling can become critical security weaknesses. Regular security assessments of office productivity software should include thorough testing of file parsing routines and memory management functions to identify similar vulnerabilities. Organizations must also consider implementing endpoint detection and response solutions that can monitor for anomalous Excel process behavior indicative of exploitation attempts. The vulnerability underscores the necessity of maintaining comprehensive software inventory and timely patch management processes to protect against known exploits.