CVE-2000-0768 in Internet Explorer
Summary
by MITRE
A function in 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, aka a variant of the "Frame Domain Verification" vulnerability.
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Analysis
by VulDB Data Team • 04/07/2017
The vulnerability identified as CVE-2000-0768 represents a critical security flaw in Microsoft Internet Explorer versions 4.x and 5.x that fundamentally compromised web browser security through improper domain verification mechanisms. This weakness specifically targeted the frame domain verification functionality that should have prevented cross-domain access violations, creating a pathway for malicious actors to bypass security boundaries that were designed to protect users from unauthorized file access. The vulnerability operates at the core of web browser security architecture where frame elements are expected to maintain strict domain isolation to prevent unauthorized data access between different websites.
The technical implementation of this flaw stems from Internet Explorer's failure to properly validate domain boundaries when processing HTML frame elements within web pages. When a malicious web page loaded in a browser window contained specially crafted frame references, the browser would incorrectly allow access to files within the local system or other domains that should have been restricted by the same-origin policy. This improper verification mechanism enabled attackers to construct web pages that could traverse domain boundaries and access sensitive client-side resources through frame manipulation techniques. The vulnerability specifically affected the way the browser handled frame navigation and domain validation, creating a window of opportunity for remote code execution and information disclosure attacks.
The operational impact of CVE-2000-0768 was severe and far-reaching, as it allowed remote attackers to execute arbitrary code on vulnerable systems and access confidential client files without user consent. Attackers could exploit this vulnerability by hosting malicious web content that would load frames from different domains and leverage the flawed verification process to read local files, potentially accessing sensitive user data, cookies, or other system resources. This vulnerability particularly affected enterprise environments where users might browse untrusted web content, as it could be exploited to gain unauthorized access to internal network resources or sensitive corporate data through client-side attacks. The attack surface was significant because it required no special privileges or user interaction beyond visiting a malicious website, making it particularly dangerous for widespread exploitation.
This vulnerability aligns with CWE-200, which addresses improper access control, and represents a classic example of how browser security mechanisms can be subverted through inadequate input validation. The attack pattern follows the typical methodology described in ATT&CK framework under T1059 for execution through web-based attacks, and T1566 for initial access via malicious websites. Organizations affected by this vulnerability faced significant risk of data breaches, system compromise, and potential lateral movement within networks where users had access to vulnerable Internet Explorer installations. The remediation required immediate patching of affected browser versions, but many organizations were slow to deploy fixes, leaving systems vulnerable to exploitation for extended periods. Security professionals had to implement additional network-level controls and user education initiatives to mitigate the risk while waiting for official patches to be distributed and deployed across affected systems.