CVE-2005-3312 in Internet Explorer
Summary
by MITRE
The HTML rendering engine in Microsoft Internet Explorer 6.0 allows remote attackers to conduct cross-site scripting (XSS) attacks via HTML in corrupted images and other files such as .GIF, JPG, and WAV, which is rendered as HTML when the user clicks on the link, even though the web server response and file extension indicate that it should be treated as a different file type.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 10/08/2018
The vulnerability described in CVE-2005-3312 represents a critical cross-site scripting flaw in Microsoft Internet Explorer 6.0's HTML rendering engine that exploits the browser's handling of file type mismatches. This vulnerability operates through a sophisticated deception mechanism where malicious actors craft files with corrupted metadata or inconsistent file signatures that appear to be one file type but contain embedded HTML code. The attack vector specifically targets the browser's content disposition handling, where Internet Explorer attempts to render file content based on its internal interpretation rather than strictly adhering to the server's content-type headers and file extensions. When users click on links to these malicious files, the browser's rendering engine processes the embedded HTML code as if it were legitimate content, creating a pathway for arbitrary code execution and session hijacking.
The technical exploitation of this vulnerability stems from Internet Explorer's lenient approach to file type validation and its reliance on heuristic content analysis when file signatures are ambiguous or inconsistent. This behavior creates a fundamental security gap in the browser's security model where file type detection becomes a potential attack surface rather than a protective mechanism. The vulnerability is particularly dangerous because it leverages the user's trust in file associations and web navigation patterns, allowing attackers to bypass traditional security measures that rely on proper file type identification. The specific file types mentioned including .GIF, .JPG, and .WAV represent common media formats that users frequently encounter and interact with, making the attack surface exceptionally broad and the potential for successful exploitation high.
From an operational impact perspective, this vulnerability enables attackers to execute malicious scripts in the context of the user's session within the Internet Explorer browser, potentially leading to complete session compromise, credential theft, and unauthorized actions on behalf of the victim. The attack requires minimal user interaction beyond clicking a link, making it particularly effective in phishing campaigns and social engineering attacks. The vulnerability affects the core rendering capabilities of Internet Explorer, which was the dominant web browser at the time of discovery, amplifying its potential impact across a massive user base. Security researchers have classified this issue under CWE-79 as a cross-site scripting vulnerability, while cybersecurity frameworks such as the MITRE ATT&CK methodology would categorize this under the T1059.007 technique for command and scripting interpreter usage through web-based attacks.
Organizations and users can mitigate this vulnerability through several defensive measures including immediate deployment of Microsoft security patches, implementing robust content filtering solutions, and configuring browser security settings to restrict automatic execution of embedded content. Network-level defenses such as web application firewalls and content inspection systems can help detect and block malicious file content before it reaches end users. Browser hardening techniques including disabling automatic image rendering of suspicious file types and implementing strict content-type validation policies provide additional layers of protection. Regular security awareness training for users to recognize suspicious links and file downloads remains crucial, as the vulnerability exploits human behavior patterns in web navigation. The incident highlights the critical importance of proper file type validation and the potential security implications of browser engines that attempt to be overly accommodating in their content interpretation.