CVE-2000-0465 in Internet Explorer
Summary
by MITRE
Internet Explorer 4.x and 5.x does not properly verify the domain of a frame within a browser window, which allows a remote attacker to read client files via the frame, aka the "Frame Domain Verification" vulnerability.
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Analysis
by VulDB Data Team • 04/21/2026
The CVE-2000-0465 vulnerability represents a critical security flaw in Internet Explorer versions 4.x and 5.x that fundamentally undermines the browser's security model through improper domain verification within frame elements. This vulnerability operates at the core of web browser security architecture, specifically targeting the cross-origin resource sharing mechanisms that should prevent unauthorized access between different domains. The flaw allows malicious actors to exploit the frame domain verification process, creating a pathway for remote code execution and unauthorized file access on client systems. This issue directly violates the fundamental security principle of same-origin policy that browsers implement to isolate content from different domains and prevent malicious interactions between them.
The technical implementation of this vulnerability stems from how Internet Explorer handled frame navigation and domain validation when processing HTML content containing frame elements. When a web page loaded in a browser window contained embedded frames that referenced content from different domains, the browser failed to properly validate whether the referenced domain matched the expected domain for security purposes. This validation failure occurred specifically in the frame loading and rendering process, where the browser would accept frame content from unauthorized domains without proper security checks. The vulnerability was particularly dangerous because it allowed attackers to craft malicious web pages that could exploit this flaw to read sensitive files from the client system, potentially including cookies, temporary files, and other locally stored data that should have been protected by the browser's security model.
The operational impact of CVE-2000-0465 was significant and far-reaching, as it provided attackers with a method to bypass browser security controls and access client-side resources without user consent or knowledge. This vulnerability enabled man-in-the-middle attacks, session hijacking, and data theft scenarios where attackers could read local files and potentially extract sensitive information stored on the victim's machine. The attack vector was particularly insidious because it required no special privileges or user interaction beyond visiting a malicious web page, making it a prime target for widespread exploitation. Security researchers identified this vulnerability as a critical risk to enterprise environments where users might visit untrusted websites, potentially leading to data breaches and unauthorized access to corporate networks through compromised client systems.
This vulnerability aligns with CWE-200, which addresses improper information exposure, and represents a classic example of how inadequate input validation and domain verification can create security holes in web browsers. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and credential access through browser exploitation, specifically targeting the web browser as an attack surface for information gathering and system compromise. The vulnerability also demonstrates the importance of proper sandboxing and isolation mechanisms in browser security models, as it shows how a flaw in frame handling can undermine the entire security architecture. Organizations affected by this vulnerability needed to implement immediate mitigations including browser updates, network-level protections, and user education to prevent exploitation, while security vendors worked to develop patches and workarounds to address the fundamental flaw in Internet Explorer's frame verification implementation.
The remediation of CVE-2000-0465 required comprehensive updates to Internet Explorer's security model and frame handling mechanisms. Microsoft released patches that strengthened domain verification processes and improved the browser's ability to properly validate frame content from different domains. Organizations needed to implement layered security approaches including network firewalls, web application firewalls, and browser security policies to prevent exploitation. The vulnerability highlighted the critical importance of regular security updates and the need for organizations to maintain current browser versions to protect against known security flaws. This incident also underscored the necessity of security testing and code review processes to identify similar domain verification issues in other software components and web applications.