CVE-2004-1133 in W3Who ISAPI
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in Microsoft W3Who ISAPI (w3who.dll) allow remote attackers to inject arbitrary HTML and web script via (1) HTTP headers such as "Connection" or (2) invalid parameters whose values are echoed in the resulting error message.
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Analysis
by VulDB Data Team • 06/04/2019
The vulnerability identified as CVE-2004-1133 represents a significant security weakness in Microsoft's Web Server 3.0 W3Who ISAPI extension component that has been classified under CWE-79 as Cross-Site Scripting. This flaw exists within the w3who.dll module which is part of the Microsoft Internet Information Services web server software. The vulnerability manifests through two distinct attack vectors that exploit the improper handling of user-supplied input data. Attackers can leverage this weakness by manipulating HTTP headers, specifically targeting the "Connection" header field, or by providing malformed parameters that trigger error messages containing unfiltered user input. These attack vectors demonstrate a fundamental failure in input validation and output encoding practices that are critical for web application security.
The technical implementation of this vulnerability stems from the W3Who ISAPI extension's inadequate sanitization of data received from client requests. When HTTP headers containing malicious scripts are processed by the w3who.dll component, the system fails to properly escape or filter the input before incorporating it into the server's response. Similarly, when invalid parameters are submitted to the web server, the resulting error messages display these parameters without appropriate encoding, creating an environment where attackers can inject malicious HTML content and JavaScript code. This behavior directly violates security best practices outlined in the OWASP Top Ten and aligns with the ATT&CK framework's T1203 technique for Exploitation for Client Execution. The vulnerability affects Microsoft Internet Information Services versions that include the W3Who ISAPI extension, making it particularly dangerous for organizations running legacy web server configurations.
The operational impact of this vulnerability extends beyond simple script injection attacks, as it provides attackers with a foothold for more sophisticated exploitation techniques. When successful, these XSS attacks can enable session hijacking, credential theft, and redirection to malicious websites. The reflected nature of the vulnerability means that attackers can craft malicious URLs that, when visited by unsuspecting users, automatically execute the injected scripts within the context of the victim's browser session. This creates a significant risk for web applications that rely on user authentication and authorization mechanisms, as attackers could potentially escalate privileges or gain unauthorized access to sensitive resources. The vulnerability's persistence across multiple HTTP header fields and parameter types increases its attack surface and makes it more difficult to defend against through simple input filtering measures.
Mitigation strategies for CVE-2004-1133 should focus on immediate remediation through official Microsoft security patches that address the input validation deficiencies in the W3Who ISAPI extension. Organizations should implement comprehensive input validation and output encoding mechanisms that follow the principle of least privilege and sanitize all user-supplied data before processing or displaying it. Network administrators should consider implementing web application firewalls that can detect and block suspicious HTTP header patterns and malformed parameter sequences. The implementation of Content Security Policy headers can provide an additional layer of protection by restricting the sources from which scripts can be executed within the browser context. Regular security assessments and vulnerability scanning should be conducted to identify similar issues in other web server components, as this vulnerability demonstrates the importance of proper input sanitization across all web application layers. Organizations should also consider migrating away from deprecated web server components that lack proper security controls and maintain up-to-date security configurations that align with current industry standards and best practices.