CVE-2004-0841 in Internet Explorer
Summary
by MITRE
Internet Explorer 6.x allows remote attackers to install arbitrary programs via mousedown events that call the Popup.show method and use drag-and-drop actions in a popup window, aka "HijackClick 3" and the "Script in Image Tag File Download Vulnerability."
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Analysis
by VulDB Data Team • 09/16/2025
The vulnerability identified as CVE-2004-0841 represents a critical security flaw in Internet Explorer 6.x versions that exploits the browser's handling of mouse events and drag-and-drop functionality to execute malicious code remotely. This vulnerability operates through a sophisticated attack vector that leverages the mousedown event handler in conjunction with the Popup.show method, creating a dangerous intersection between user interaction and code execution. The flaw specifically targets the browser's popup window management system, where attackers can manipulate the drag-and-drop actions to trigger unauthorized program installations on vulnerable systems.
The technical implementation of this vulnerability stems from Internet Explorer's insufficient validation of mouse events within popup contexts, particularly when the Popup.show method is invoked. When a user interacts with a malicious webpage through mousedown events, the browser's event handling mechanism fails to properly sanitize the drag-and-drop operations that occur within popup windows. This allows attackers to craft HTML content that appears benign but actually executes malicious code through the underlying browser engine's handling of these specific event sequences. The vulnerability essentially creates a pathway for privilege escalation through user interaction, where legitimate browser functionality becomes weaponized against users.
From an operational perspective, this vulnerability presents a significant threat to enterprise environments and individual users alike, as it enables remote code execution without requiring any special privileges or user consent. The attack requires only a user to visit a malicious webpage, making it particularly dangerous for targeted campaigns and social engineering attacks. The "HijackClick 3" moniker reflects the technique's ability to hijack click events and redirect them to execute arbitrary programs, while the "Script in Image Tag File Download Vulnerability" component indicates how attackers can leverage image tags to download and execute malicious scripts. This vulnerability aligns with CWE-20, which addresses improper input validation, and demonstrates how seemingly innocuous browser features can be exploited to create persistent security threats.
The attack methodology involves crafting malicious HTML content that triggers the vulnerable popup behavior through mouse events, followed by drag-and-drop operations that ultimately execute malicious code on the target system. This approach allows attackers to bypass traditional security measures such as popup blockers and script restrictions, as the malicious code executes within the legitimate browser context. The vulnerability's impact extends beyond simple code execution to include potential system compromise, data theft, and persistent backdoor installation. Organizations running Internet Explorer 6.x systems were particularly vulnerable due to the browser's widespread deployment and the lack of modern security features present in later browser versions.
Mitigation strategies for this vulnerability required immediate patching of Internet Explorer 6.x installations, as well as implementing network-level security controls to block malicious content. The remediation process involved updating the browser to versions that addressed the underlying event handling flaws and implementing stricter content filtering mechanisms. Security professionals recommended disabling drag-and-drop functionality in browser settings and employing enhanced web application firewalls to detect and block malicious payloads. This vulnerability highlighted the importance of proper event validation in web browsers and contributed to the development of more robust security measures in subsequent browser versions. The attack pattern associated with CVE-2004-0841 has been catalogued in various threat intelligence databases and represents one of the early examples of browser-based privilege escalation techniques that influenced the development of modern browser security architectures and the ATT&CK framework's categorization of browser exploitation techniques.