CVE-2002-0242 in Internet Explorer
Summary
by MITRE
Cross-site scripting vulnerability in Internet Explorer 6 earlier allows remote attackers to execute arbitrary script via an Extended HTML Form, whose output from the remote server is not properly cleansed.
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Analysis
by VulDB Data Team • 04/07/2017
The vulnerability described in CVE-2002-0242 represents a classic cross-site scripting flaw that affected Internet Explorer 6.0 and earlier versions, demonstrating the critical importance of input validation and output sanitization in web applications. This security weakness allowed malicious actors to inject arbitrary JavaScript code into web pages that would be executed in the context of other users' browsers, fundamentally compromising the security model of web-based applications. The vulnerability specifically manifested when Internet Explorer processed Extended HTML Form elements, where server-side output was not adequately sanitized before being rendered to end users.
The technical root cause of this vulnerability stems from inadequate input validation mechanisms within Internet Explorer's rendering engine. When the browser encountered Extended HTML Form elements containing malicious script code, it failed to properly escape or filter special characters that could be interpreted as executable commands. This flaw falls under the CWE-79 category of Cross-site Scripting, which specifically addresses the injection of malicious code into web applications. The vulnerability exploited the browser's trust in server-generated content without sufficient sanitization, creating a pathway for attackers to bypass security boundaries that should normally protect users from executing unauthorized code.
The operational impact of this vulnerability was severe and far-reaching, as it enabled attackers to perform a wide range of malicious activities including session hijacking, credential theft, and data exfiltration. An attacker could craft malicious URLs or form submissions that would execute scripts in the context of authenticated users, potentially allowing them to access sensitive information or perform unauthorized actions on behalf of victims. This type of vulnerability particularly affected web applications that dynamically generated content based on user input, making it a critical concern for any organization relying on web-based services. The attack vector was particularly insidious because it required no special privileges from the attacker beyond the ability to influence server-side content generation.
Mitigation strategies for this vulnerability centered on both client-side and server-side approaches. Organizations needed to implement comprehensive input validation and output encoding mechanisms to prevent script injection attempts, with server-side sanitization being the primary defense. The recommended approach involved escaping special characters such as angle brackets, quotes, and script tags in all user-supplied content before rendering it in web pages. Additionally, implementing proper content security policies and using modern browser security features like XSS protection headers would have provided additional layers of defense. This vulnerability highlighted the necessity of following secure coding practices and adhering to established security frameworks such as those recommended by the Open Web Application Security Project, emphasizing the critical need for comprehensive security testing and validation of web applications against known attack patterns. The incident underscored the importance of keeping browser software updated and implementing proper security configurations to prevent exploitation of known vulnerabilities.