CVE-2001-0246 in Internet Explorer
Summary
by MITRE
Internet Explorer 5.5 and earlier does not properly verify the domain of a frame within a browser window, which allows remote web site operators to read certain files on the client by sending information from a local frame to a frame in a different domain, aka a variant of the "Frame Domain Verification" vulnerability.
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Analysis
by VulDB Data Team • 06/19/2024
This vulnerability represents a critical cross-domain security flaw in Microsoft Internet Explorer versions 5.5 and earlier, specifically targeting the browser's frame domain verification mechanisms. The issue stems from insufficient validation of cross-domain frame relationships, allowing malicious web sites to exploit the browser's trust model to access local resources that should be restricted. This weakness enables attackers to bypass the standard security boundaries that normally prevent frames from different domains from communicating with each other, creating a pathway for unauthorized data exfiltration.
The technical implementation of this vulnerability exploits the browser's frame hierarchy and security model by leveraging the fact that older versions of Internet Explorer did not properly enforce domain-based security restrictions when handling nested frames. When a web page loads frames from different domains, the browser should normally prevent access between these frames to maintain security boundaries. However, this flaw allowed attackers to craft malicious pages that could manipulate frame relationships to access local files through cross-domain communication channels. The vulnerability specifically affects the domain verification process that should occur when frames attempt to access each other's content or properties across domain boundaries.
The operational impact of this vulnerability is significant as it enables remote attackers to perform unauthorized file access on compromised systems. An attacker could construct a malicious web page that loads a local frame and then uses JavaScript to communicate with frames from different domains, potentially accessing sensitive local files that are normally protected by the browser's security model. This creates a scenario where a remote web site operator can read files from the client system that should be restricted to the local domain, potentially exposing user data, system information, or other sensitive resources. The vulnerability essentially undermines the fundamental security principle that different domains should be isolated from each other within the browser environment.
The flaw aligns with CWE-200, which addresses "Information Exposure," and represents a classic example of how insufficient input validation and security boundary enforcement can lead to privilege escalation and data exposure. From an attack perspective, this vulnerability maps to ATT&CK technique T1059, specifically involving the use of scripting languages to execute malicious code, and T1566, which covers the use of malicious web content to gain initial access. The vulnerability also relates to T1071, where adversaries use application layer protocols to conduct their operations. Organizations affected by this vulnerability should implement immediate mitigations including browser updates, disabling frame-based communication where possible, and implementing network-level restrictions to prevent access to known malicious domains. The recommended approach involves upgrading to supported browser versions that properly enforce domain verification mechanisms, along with implementing content security policies that restrict cross-domain frame access and monitoring for suspicious frame communication patterns.
This vulnerability demonstrates the importance of proper security boundary enforcement in web browsers and highlights how legacy security implementations can create dangerous attack vectors. The issue underscores the critical need for robust domain verification mechanisms in browser security models and emphasizes the risks associated with outdated software components that may lack modern security controls. Organizations should treat this as a high-priority vulnerability requiring immediate remediation through browser updates and security policy enforcement to prevent potential exploitation by threat actors.