CVE-2004-2383 in Internet Explorer
Summary
by MITRE
Microsoft Internet Explorer 5.0 through 6.0 allows remote attackers to bypass cross-frame scripting restrictions and capture keyboard events from other domains via an HTML document with Javascript that is outside a frameset that includes the target domain, then forcing the frameset to maintain focus. NOTE: the discloser claimed that the vendor does not categorize this as a vulnerability, but it can be used in a spoofing scenario; the discloser provides alternate scenarios. Spoofing scenarios are currently included in CVE.
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Analysis
by VulDB Data Team • 09/16/2025
This vulnerability exists in Microsoft Internet Explorer versions 5.0 through 6.0 and represents a significant cross-frame scripting restriction bypass that enables attackers to capture keyboard events from different domains. The flaw occurs when an attacker crafts an HTML document containing javascript code that operates outside of a frameset structure that includes the target domain. This specific configuration allows the malicious code to maintain focus over the frameset, effectively circumventing the browser's security mechanisms designed to prevent cross-domain script execution. The vulnerability specifically targets the browser's handling of focus management and frame security boundaries, creating an unexpected pathway for malicious actors to access sensitive user input from other domains.
The technical implementation of this exploit relies on the browser's failure to properly enforce security boundaries when managing focus within frame environments. When a frameset contains multiple frames from different domains, the standard security model should prevent scripts in one frame from accessing or monitoring input from another frame. However, this vulnerability allows attackers to manipulate the focus state in such a way that keyboard events from the target domain can be captured and potentially transmitted to the attacker's server. The flaw demonstrates a weakness in the browser's security model where focus management does not properly account for cross-domain access restrictions, creating a vector for information disclosure and user interaction hijacking.
The operational impact of this vulnerability is substantial as it enables sophisticated phishing and spoofing attacks that can capture user credentials and sensitive input from legitimate websites. Attackers can create malicious pages that appear to be from trusted domains while simultaneously monitoring user keystrokes from other frames within the same frameset. This capability undermines the fundamental security principle of domain isolation that browsers enforce to protect users from cross-site scripting attacks. The vulnerability is particularly dangerous because it can be used in conjunction with social engineering techniques to create highly convincing spoofing scenarios where users believe they are interacting with legitimate services while their input is being captured by malicious actors. This type of attack directly impacts user trust and can lead to significant financial and data loss incidents.
Organizations should implement immediate mitigations including disabling framesets in web applications where possible, implementing proper content security policies, and educating users about the risks of visiting untrusted websites. Browser vendors should ensure proper focus management and cross-domain security boundary enforcement, with specific attention to how framesets handle focus states and domain isolation. This vulnerability aligns with CWE-200, which covers information exposure, and CWE-202, which addresses information exposure through improper focus management in web applications. The attack pattern corresponds to ATT&CK technique T1190, which involves exploiting vulnerabilities in web applications, and T1185, which covers data from local system. The security community should consider this vulnerability as part of a broader class of focus-related security issues that affect browser implementations and require careful attention to proper focus state management and cross-domain access controls.