CVE-2002-0193 in Internet Explorer
Summary
by MITRE
Microsoft Internet Explorer 5.01 and 6.0 allow remote attackers to execute arbitrary code via malformed Content-Disposition and Content-Type header fields that cause the application for the spoofed file type to pass the file back to the operating system for handling rather than raise an error message, aka the first variant of the "Content Disposition" vulnerability.
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Analysis
by VulDB Data Team • 06/15/2025
This vulnerability represents a critical security flaw in Microsoft Internet Explorer versions 5.01 and 6.0 that enables remote code execution through crafted HTTP header manipulation. The vulnerability specifically targets the browser's handling of Content-Disposition and Content-Type header fields, which are standard HTTP headers used to indicate how content should be processed and displayed by web browsers. When these headers are malformed or improperly constructed, the browser's file type detection mechanism fails to properly validate the content, creating a pathway for malicious code execution. The flaw operates at the application layer of the network stack, specifically within the HTTP response processing component of the web browser, making it particularly dangerous as it can be exploited through standard web browsing activities without requiring any special privileges or user interaction beyond visiting a malicious website.
The technical mechanism behind this vulnerability involves the browser's failure to properly sanitize or validate the Content-Disposition header values, which are designed to instruct the browser on how to handle file attachments. When an attacker crafts malicious headers that appear to indicate a benign file type such as text/plain or image/jpeg, but the actual content contains executable code, the browser incorrectly processes these headers and passes the file to the operating system's file handler for processing. This behavior violates the principle of least privilege and allows the system to execute potentially malicious code without proper security checks. The vulnerability is classified under CWE-119 as a weakness related to improper restriction of operations within a restricted environment, specifically concerning memory access violations and improper handling of file type associations. This type of vulnerability falls under the ATT&CK framework's technique T1059 for command and scripting interpreter, where adversaries leverage browser-based attacks to execute arbitrary code on target systems.
The operational impact of this vulnerability is severe as it allows attackers to remotely compromise systems running vulnerable versions of Internet Explorer without requiring user interaction beyond visiting a malicious webpage. The attack vector is particularly dangerous because it leverages the browser's trust relationship with the operating system's file handling mechanisms, effectively bypassing traditional security boundaries. Systems that have default file associations configured to automatically execute certain file types when opened become vulnerable to this attack, as the browser essentially delegates the responsibility of file handling to the operating system without proper validation. The vulnerability creates a chain of execution where the malicious payload is first downloaded through a web request, then processed through the browser's header parsing, and finally executed through the operating system's file association handlers. This multi-layered attack approach makes detection and prevention particularly challenging, as it spans across different security domains including web browser security, operating system file handling, and network protocol processing.
Mitigation strategies for this vulnerability require a multi-faceted approach that addresses both the immediate security gap and broader system protection measures. Organizations should implement immediate patches from Microsoft that correct the header parsing logic and enforce proper validation of Content-Disposition and Content-Type headers. Additionally, security configurations should include disabling automatic execution of downloaded files, implementing strict file type validation policies, and configuring browser security settings to limit automatic file handling behaviors. Network-level protections such as web application firewalls and content filtering systems can help detect and block malicious headers before they reach vulnerable browsers. The vulnerability also highlights the importance of maintaining up-to-date software versions and implementing security awareness training to help users recognize potentially malicious web content. System administrators should also consider implementing application whitelisting policies that restrict which file types can be automatically executed by the operating system, thereby limiting the potential impact of successful exploitation attempts. Regular security assessments and vulnerability scanning should be conducted to identify and remediate similar weaknesses in other browser versions and related software components.