CVE-2002-0269 in Internet Explorer
Summary
by MITRE
Internet Explorer 5.x and 6 interprets an object as an HTML document even when its MIME Content-Type is text/plain, which could allow remote attackers to execute arbitrary script in documents that the user does not expect, possibly through web applications that use a text/plain type to prevent cross-site scripting attacks.
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Analysis
by VulDB Data Team • 05/07/2019
This vulnerability exists in internet explorer versions 5.x and 6 where the browser exhibits improper handling of content type headers during document parsing. when a web server delivers content with a text/plain mime type, internet explorer still attempts to interpret the content as an html document, bypassing the intended security restrictions. this behavior creates a significant security risk as it allows malicious actors to exploit the browser's content interpretation logic to execute arbitrary javascript code within the context of the user's session.
the technical flaw stems from internet explorer's content sniffing mechanism which operates independently of the declared content type header. this mechanism attempts to determine the appropriate rendering method based on the actual content structure rather than strictly adhering to the mime type specification. when content with text/plain headers contains html markup or script elements, the browser's interpretation engine still processes these elements as if they were part of an html document. this violates the principle of least privilege and content type validation that security-conscious web applications rely upon.
the operational impact of this vulnerability is particularly severe as it directly undermines cross-site scripting prevention mechanisms that web developers implement. many applications deliberately set text/plain content types to prevent script execution in user-supplied content, assuming that browsers will respect this header. however, internet explorer's behavior renders these protections ineffective, allowing attackers to inject and execute malicious scripts in contexts where they would normally be blocked. this creates a persistent threat vector that can be exploited through various attack surfaces including user input fields, file uploads, and dynamic content generation.
the vulnerability aligns with several common weakness enumerations including cwe-20 improper input validation and cwe-116 improper encoding or escaping. it also maps to attack techniques in the mitre att&ck framework under initial access and execution phases where adversaries leverage browser vulnerabilities to establish malicious code execution. organizations using these vulnerable browser versions face significant risk of credential theft, session hijacking, and persistent malware installation through this vector.
mitigation strategies should focus on immediate browser updates to supported versions that properly handle content type headers. administrators should implement content security policies that explicitly define allowed script sources and prevent execution of inline scripts. network-level controls including web application firewalls can help detect and block suspicious content patterns. developers should avoid relying solely on content type headers for security enforcement and implement additional input validation and sanitization measures. the most effective long-term solution involves complete browser version migration away from vulnerable internet explorer releases to modern browsers with proper security implementations and regular update cycles.