CVE-2002-0461 in Internet Explorer
Summary
by MITRE
Internet Explorer 5.01 through 6 allows remote attackers to cause a denial of service (application crash) via Javascript in a web page that calls location.replace on itself, causing a loop.
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Analysis
by VulDB Data Team • 04/21/2025
The vulnerability identified as CVE-2002-0461 represents a classic denial of service flaw in Microsoft Internet Explorer versions 5.01 through 6.0 that demonstrates how seemingly benign JavaScript operations can be exploited to create catastrophic application instability. This vulnerability specifically targets the browser's handling of the location.replace method when invoked on the current page, creating an infinite loop that consumes system resources and ultimately causes the browser application to crash. The flaw operates at the core of web browser security architecture where proper handling of navigation operations should prevent such recursive behaviors from occurring.
The technical mechanism behind this vulnerability involves the JavaScript engine's failure to properly detect and terminate recursive calls to location.replace when executed against the same document. When a malicious web page executes location.replace(window.location.href), the browser attempts to replace the current document with itself, creating an infinite loop where the browser continuously attempts to reload the same page. This recursive behavior bypasses normal browser safeguards designed to prevent such operations and consumes excessive memory and processor cycles until the application becomes unresponsive. The vulnerability resides in the browser's JavaScript interpreter and DOM manipulation handling, making it particularly dangerous as it can be triggered simply by visiting a malicious webpage without any user interaction beyond normal browsing.
From an operational perspective, this vulnerability poses significant risks to users who may inadvertently visit compromised websites or encounter malicious content through phishing attacks, drive-by downloads, or compromised web applications. The impact extends beyond simple application instability as it can be leveraged as part of broader attack campaigns where attackers use the denial of service capability to disrupt user productivity or as a precursor to more sophisticated attacks. The vulnerability affects a wide range of users since Internet Explorer 5.01 through 6.0 were widely deployed across corporate and personal environments during the early 2000s, making the attack surface particularly large. Network administrators and security professionals would need to implement immediate mitigations to protect their user bases from exploitation.
The vulnerability aligns with CWE-674, which describes "Uncontrolled Recursion" in software systems, specifically highlighting the lack of proper recursion detection and termination mechanisms in the browser's JavaScript execution environment. From an ATT&CK framework perspective, this vulnerability maps to T1499.004, which covers "Utilities: System Shutdown/Reboot," as the denial of service effectively renders the browser application unavailable to users. Additionally, the vulnerability demonstrates characteristics of T1059.007, "Command and Scripting Interpreter: JavaScript," where malicious JavaScript code is executed to achieve the desired effect. Organizations should implement browser security updates and patches as the primary mitigation, while also considering network-level protections such as web proxies that can filter out known malicious JavaScript patterns. User education about avoiding untrusted websites and implementing browser security restrictions through group policies or security toolsets can provide additional layers of defense against exploitation attempts.
This vulnerability highlights the critical importance of proper input validation and recursion detection in web browser implementations. The flaw demonstrates how inadequate bounds checking in JavaScript engines can lead to resource exhaustion and application instability, emphasizing the need for robust defensive programming practices in browser security architecture. The widespread impact of this vulnerability across multiple Internet Explorer versions underscores the necessity of comprehensive patch management strategies and the importance of maintaining up-to-date browser security implementations to prevent exploitation of known vulnerabilities.