CVE-2004-1050 in Internet Explorer
Summary
by MITRE
Heap-based buffer overflow in Internet Explorer 6 allows remote attackers to execute arbitrary code via long (1) SRC or (2) NAME attributes in IFRAME, FRAME, and EMBED elements, as originally discovered using the mangleme utility, aka "the IFRAME vulnerability" or the "HTML Elements Vulnerability."
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Analysis
by VulDB Data Team • 09/17/2025
The CVE-2004-1050 vulnerability represents a critical heap-based buffer overflow in Internet Explorer 6 that fundamentally compromised web browser security through improper handling of HTML elements. This vulnerability specifically targeted the processing of SRC and NAME attributes within IFRAME, FRAME, and EMBED HTML elements, creating a dangerous attack vector that could be exploited remotely without user interaction. The flaw emerged from inadequate input validation and memory management practices within the browser's HTML parser, allowing attackers to craft malicious web pages that would trigger the overflow when these elements were processed. The vulnerability was particularly significant because it affected one of the most widely used web browsers of its time, making it a prime target for widespread exploitation and demonstrating the critical importance of proper memory management in client-side applications.
The technical implementation of this vulnerability stems from a classic heap-based buffer overflow condition where the browser's handling of HTML attribute values exceeds the allocated memory boundaries. When Internet Explorer 6 encountered excessively long SRC or NAME attribute values within IFRAME, FRAME, or EMBED elements, the application failed to properly validate the input length before copying it into fixed-size memory buffers. This memory corruption occurred in the heap memory space, making exploitation more complex but also more dangerous than stack-based overflows. The mangleme utility, which was originally used to discover this vulnerability, demonstrated how carefully crafted attribute values could trigger the buffer overflow by exploiting the difference between the expected buffer size and the actual length of the malicious input. The vulnerability mapped to CWE-121, which describes heap-based buffer overflow conditions, and represented a direct violation of secure coding practices that require bounds checking on all input data.
The operational impact of CVE-2004-1050 was devastating and far-reaching, as it enabled remote code execution attacks that could compromise entire user systems without requiring any user interaction or privilege escalation. Attackers could host malicious web pages that would automatically execute arbitrary code when viewed in Internet Explorer 6, potentially leading to complete system compromise, data theft, or deployment of additional malware. The vulnerability was particularly dangerous because it could be exploited through various attack vectors including web-based attacks, phishing campaigns, and drive-by downloads, making it extremely difficult for users to protect themselves. The widespread adoption of Internet Explorer 6 at the time meant that a large portion of internet users were potentially vulnerable to this attack, creating a significant security risk for organizations and individuals alike. This vulnerability exemplified the ATT&CK technique of exploitation through web-based attacks, specifically targeting the web browser as a primary attack surface.
Mitigation strategies for CVE-2004-1050 focused on immediate patching and browser updates, as Microsoft released a security update to address the heap overflow condition in Internet Explorer 6. Organizations had to implement comprehensive security measures including browser hardening, network-based filtering, and user education to reduce exposure to this vulnerability. The vulnerability highlighted the importance of secure coding practices and proper input validation, leading to enhanced security guidelines for web browser development. Additional mitigations included implementing web application firewalls, restricting access to potentially malicious websites, and deploying intrusion detection systems to monitor for exploitation attempts. The incident underscored the necessity of regular security updates and the critical role of vulnerability management in maintaining secure computing environments, particularly for widely deployed software applications that serve as primary attack vectors for cybercriminals.