CVE-2003-1505 in Internet Explorer
Summary
by MITRE
Microsoft Internet Explorer 6.0 allows remote attackers to cause a denial of service (crash) by creating a web page or HTML e-mail with a textarea in a div element whose scrollbar-base-color is modified by a CSS style, which is then moved.
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Analysis
by VulDB Data Team • 02/01/2025
This vulnerability resides in Microsoft Internet Explorer 6.0 and represents a classic denial of service flaw that exploits the browser's handling of cascading style sheets and DOM manipulation. The issue specifically occurs when a malicious web page or HTML email contains a textarea element nested within a div container where the scrollbar base color is modified through CSS styling. When this particular combination of HTML structure and CSS properties is processed by IE6, it triggers an internal memory management error that leads to application crash and complete browser termination.
The technical root cause of this vulnerability stems from inadequate input validation and memory handling within IE6's rendering engine when processing complex CSS properties in conjunction with dynamic DOM elements. The vulnerability specifically targets the browser's scrollbar rendering subsystem which is responsible for managing scrollable content areas. When the CSS style scrollbar-base-color is applied to a textarea element contained within a div that is subsequently moved or repositioned through JavaScript or CSS positioning, the browser's internal memory structures become corrupted. This corruption manifests as a heap overflow or invalid memory access condition that causes the browser process to terminate unexpectedly.
The operational impact of this vulnerability extends beyond simple service disruption as it represents a potential vector for more sophisticated attacks. While the primary effect is a denial of service that renders the browser unusable to the victim, this flaw could be leveraged as part of a broader attack strategy to compromise user sessions or deliver additional malicious content. The vulnerability affects all users running IE6 regardless of their security settings or patch status, making it particularly dangerous in enterprise environments where legacy browser support is still required. Security researchers have categorized this issue under CWE-129, which addresses improper validation of length of input buffers, and it aligns with ATT&CK technique T1499.004 for network denial of service attacks.
Mitigation strategies for this vulnerability require immediate action through patch management and browser upgrade initiatives. Microsoft released security updates addressing this specific issue in subsequent service packs for IE6, though the recommended long-term solution involves migrating away from IE6 entirely due to its numerous unpatched vulnerabilities. Organizations should implement web content filtering to block malicious HTML content containing problematic CSS combinations, while also considering browser sandboxing techniques to contain potential exploitation attempts. The vulnerability highlights the importance of proper input sanitization and memory management in web browser implementations, serving as a reminder that even seemingly benign CSS properties can create critical security flaws when combined with dynamic DOM manipulation. Security teams should also consider implementing network-based intrusion detection systems that can identify and block attempts to deliver malicious HTML content with these specific patterns to protect against exploitation attempts.