CVE-2004-0846 in Excel
Summary
by MITRE
Unknown vulnerability in Microsoft Excel 2000, 2002, 2001 for Mac, and v.X for Mac allows remote attackers to execute arbitrary code via a malicious file containing certain parameters that are not properly validated.
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Analysis
by VulDB Data Team • 07/07/2025
This vulnerability resides within Microsoft Excel versions 2000, 2002, 2001 for Mac, and v.X for Mac, representing a critical code execution flaw that arises from insufficient input validation mechanisms. The vulnerability specifically manifests when Excel processes malicious files containing crafted parameters that are not properly validated during the parsing phase, creating an exploitable condition that allows remote attackers to execute arbitrary code on affected systems. This issue constitutes a classic buffer overflow vulnerability pattern where malformed input data can overwrite memory segments, leading to unauthorized code execution. The flaw operates at the application layer and represents a significant security weakness that directly violates the principle of input validation and sanitization. From a cybersecurity perspective, this vulnerability demonstrates how legacy software systems often contain unpatched security gaps that can be exploited remotely without user interaction, making them particularly dangerous in enterprise environments where Excel is widely deployed.
The technical implementation of this vulnerability stems from improper validation of file parameters during Excel's file parsing operations, which falls under the CWE-125 weakness category for out-of-bounds read conditions and potentially CWE-787 for out-of-bounds write conditions. When Excel encounters a maliciously crafted file, the application fails to validate the structure and content of specific parameters within the file format, allowing attackers to manipulate memory layout and execute malicious code with the privileges of the user running Excel. The attack vector is remote and does not require user interaction beyond opening the malicious file, making it particularly dangerous in phishing scenarios or when files are automatically processed by email clients or web browsers. This vulnerability represents a classic example of how insufficient bounds checking in legacy software can create persistent security risks that remain exploitable long after initial discovery.
The operational impact of this vulnerability extends beyond simple code execution to encompass complete system compromise, as attackers can leverage this weakness to establish persistent access, escalate privileges, and potentially move laterally within network environments. Organizations utilizing these older Excel versions face significant risk exposure, particularly in environments where users frequently open files from untrusted sources or where automated file processing occurs. The vulnerability's remote exploitability means that attackers can target users from anywhere on the internet without requiring physical access to the target system, making it an attractive target for cybercriminals and nation-state actors. Additionally, the widespread deployment of these legacy Excel versions across enterprise networks creates a substantial attack surface that can be exploited to gain initial access to sensitive corporate data and infrastructure.
Mitigation strategies for this vulnerability require immediate action including mandatory software updates and patches from Microsoft, which would address the underlying input validation flaws in affected Excel versions. Organizations should implement strict file validation policies that prevent automatic execution of potentially malicious files, particularly those from external sources or untrusted domains. Network-level controls such as email filtering and web proxies can help prevent users from inadvertently opening malicious files, while endpoint protection solutions should be configured to monitor for suspicious file execution patterns. From a defensive perspective, this vulnerability highlights the importance of maintaining up-to-date software versions and implementing robust patch management processes, as the ATT&CK framework categorizes this type of vulnerability under T1059 for command and script interpreter and T1133 for external remote services, demonstrating how such flaws enable broader attack chains. System administrators should also consider implementing application whitelisting policies that restrict execution of unauthorized Office applications, particularly in high-security environments where legacy software must be maintained for business continuity reasons.