CVE-2004-0839 in Internet Explorer
Summary
by MITRE
Internet Explorer in Windows XP SP2, and other versions including 5.01 and 5.5, allows remote attackers to install arbitrary programs via a web page that uses certain styles and the AnchorClick behavior, popup windows, and drag-and-drop capabilities to drop the program in the local startup folder, as demonstrated by "wottapoop.html".
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Analysis
by VulDB Data Team • 01/02/2025
This vulnerability represents a sophisticated privilege escalation flaw in Microsoft Internet Explorer that leverages multiple browser capabilities to execute arbitrary code on affected systems. The vulnerability specifically affects Windows XP Service Pack 2 and earlier versions including Internet Explorer 5.01 and 5.5, exploiting a combination of CSS styling features, browser behaviors, and window management functions to achieve unauthorized program installation. The attack vector utilizes the AnchorClick behavior which is a deprecated feature that allows web pages to execute scripts when anchor elements are clicked, combined with popup window creation capabilities and drag-and-drop functionality to manipulate the local file system.
The technical exploitation mechanism involves crafting a malicious web page that employs specific CSS styles to trigger the vulnerable behaviors within Internet Explorer's rendering engine. When a user visits the malicious page, the browser's implementation of the AnchorClick behavior combined with popup window creation allows the attacker to manipulate the browser's security context. The drag-and-drop capabilities are then leveraged to transfer executable files from the web page to the local system, specifically targeting the Windows startup folder where programs automatically execute during system boot. This particular exploitation technique demonstrates a deep understanding of Internet Explorer's security model and how legacy features can be abused to bypass security boundaries.
The operational impact of this vulnerability is significant as it allows remote attackers to establish persistent presence on compromised systems without requiring user interaction beyond visiting a malicious web page. The attack achieves automatic program installation in the startup folder, which means that once the system reboots, the malicious program will execute automatically, providing the attacker with persistent access and control. This vulnerability falls under the CWE-119 weakness category, which deals with weaknesses that allow for improper restriction of operations within the bounds of a memory buffer, and specifically relates to improper access control and privilege escalation. The vulnerability also maps to ATT&CK technique T1059.001 for command and scripting interpreter and T1068 for exploit for privilege escalation, demonstrating how a browser-based vulnerability can be leveraged for broader system compromise.
The exploitation technique described in the vulnerability demonstrates a sophisticated understanding of browser security boundaries and how legacy features can be abused to achieve code execution. The use of wottapoop.html as a demonstration payload indicates that this vulnerability was actively exploited in the wild, making it a critical concern for organizations running affected versions of Internet Explorer. Organizations should note that this vulnerability represents a classic example of how browser-based attacks can be used to establish persistence, and the attack methodology should be considered when evaluating overall security posture. The vulnerability highlights the importance of keeping browsers updated and the dangers of enabling deprecated browser features that may not be properly secured against abuse. System administrators should implement network-based protections and consider disabling unnecessary browser behaviors to mitigate the risk of exploitation.