CVE-2003-0662 in Windows
Summary
by MITRE
Buffer overflow in Troubleshooter ActiveX Control (Tshoot.ocx) in Microsoft Windows 2000 SP4 and earlier allows remote attackers to execute arbitrary code via an HTML document with a long argument to the RunQuery2 method.
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Analysis
by VulDB Data Team • 08/11/2025
The vulnerability identified as CVE-2003-0662 represents a critical buffer overflow flaw within the Troubleshooter ActiveX Control component of Microsoft Windows 2000 systems. This specific vulnerability affects Windows 2000 Service Pack 4 and earlier versions, making it particularly concerning given the widespread deployment of this operating system during that era. The Troubleshooter ActiveX Control, known as Tshoot.ocx, is designed to assist users in diagnosing and resolving system issues through automated troubleshooting processes. However, this component contains a fundamental flaw that can be exploited by malicious actors to gain unauthorized code execution privileges on affected systems.
The technical nature of this vulnerability stems from improper input validation within the RunQuery2 method of the Tshoot.ocx ActiveX control. When an HTML document containing a malformed argument is processed by Internet Explorer, the control fails to properly bounds-check the input data before copying it into a fixed-size buffer. This classic buffer overflow condition occurs because the application does not verify that the input data length exceeds the allocated buffer space, allowing an attacker to overwrite adjacent memory locations. The flaw specifically manifests when the attacker supplies an excessively long argument to the RunQuery2 method, which triggers the overflow condition in the vulnerable ActiveX control's memory management routines.
The operational impact of this vulnerability extends far beyond simple denial of service scenarios, as it provides remote attackers with the capability to execute arbitrary code with the privileges of the user running the affected application. This means that if a user visits a malicious website containing the exploit, the attacker can potentially gain complete control over the victim's system without requiring any local access or authentication. The vulnerability is particularly dangerous because it leverages the trust relationship that exists between ActiveX controls and web browsers, allowing malicious code to be executed directly within the browser context. According to CWE-121, this vulnerability falls under the category of stack-based buffer overflow conditions, which are among the most prevalent and dangerous classes of software vulnerabilities in legacy Windows applications.
The exploitation of this vulnerability aligns with several tactics described in the MITRE ATT&CK framework, particularly those related to initial access and execution phases of cyber attacks. Attackers can leverage this vulnerability through malicious websites or email attachments that contain specially crafted HTML documents designed to trigger the buffer overflow when the user's browser loads the content. The attack vector demonstrates the classic characteristics of a remote code execution vulnerability where network-based attacks can be launched without requiring physical access to the target system. The vulnerability's presence in widely deployed Windows 2000 systems meant that it could potentially affect thousands of endpoints across organizations that had not yet implemented security patches or migrated to newer operating systems.
Organizations affected by this vulnerability should implement immediate mitigations including applying the Microsoft security patch released in response to this vulnerability, disabling ActiveX controls in web browsers, and implementing network-based security controls to block access to known malicious domains. The patch addresses the root cause by implementing proper bounds checking in the RunQuery2 method of the Tshoot.ocx control, preventing the buffer overflow condition from occurring. Additionally, security administrators should consider deploying web application firewalls and implementing strict browser security policies that limit ActiveX control execution, particularly in environments where users may encounter untrusted content. The vulnerability serves as a prime example of why proper input validation and memory safety practices are essential in software development, particularly for components that interact with user-supplied data in web-based environments.