CVE-2001-1489 in Internet Explorer
Summary
by MITRE
Microsoft Internet Explorer 6 allows remote attackers to cause a denial of service (CPU consumption and memory leak) via a web page with a large number of images.
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Analysis
by VulDB Data Team • 12/06/2024
This vulnerability affects Microsoft Internet Explorer 6 and represents a classic resource exhaustion attack pattern that has persisted across various web browsers and operating systems. The flaw manifests when a malicious web page contains an excessive number of images, causing the browser to consume excessive cpu cycles and memory resources during the rendering process. This type of vulnerability falls under the broader category of denial of service attacks that target application resource management rather than direct system compromise. The vulnerability is particularly concerning because it can be triggered through simple web browsing activities without requiring any special privileges or user interaction beyond visiting a malicious website.
The technical implementation of this vulnerability stems from how Internet Explorer 6 handles image rendering and memory allocation when processing web pages with high image density. When the browser encounters a page containing numerous images, it attempts to load and render each image sequentially, leading to progressive memory allocation and cpu utilization. The browser fails to implement adequate resource limits or optimization mechanisms to handle such scenarios, resulting in either complete system unresponsiveness or significant performance degradation. This behavior aligns with CWE-400, which categorizes uncontrolled resource consumption as a fundamental weakness in software design. The vulnerability demonstrates poor input validation and resource management practices that allow attackers to exploit the application's inability to handle excessive data loads gracefully.
The operational impact of this vulnerability extends beyond simple service disruption to potentially affect system stability and availability. When exploited, the targeted system may experience complete browser freeze, system slowdowns, or even complete system crashes depending on available resources. This makes the vulnerability particularly dangerous in environments where browser stability is critical, such as kiosks, public terminals, or corporate workstations. The attack vector is relatively simple and can be delivered through standard web traffic, making it accessible to attackers with minimal technical expertise. From an attacker perspective, this represents a low-effort, high-impact method for disrupting services, as it requires only the creation of a malicious web page with sufficient image density to trigger the resource exhaustion condition.
Mitigation strategies for this vulnerability should focus on both application-level and network-level protections. Browser vendors should implement resource limits and optimization techniques to prevent uncontrolled memory allocation during image processing, which aligns with ATT&CK technique T1499.100 for resource exhaustion. Users should employ updated browser versions that have addressed these issues, as Microsoft released patches for this vulnerability in subsequent updates. Network administrators can implement web filtering solutions and content inspection mechanisms to block known malicious sites. Additionally, system administrators should consider implementing browser sandboxing and resource monitoring to detect and prevent such resource exhaustion attacks. The vulnerability underscores the importance of proper resource management in web applications and highlights the need for robust input validation and resource limiting mechanisms to prevent similar issues from occurring in modern web browsers and applications.