CVE-2002-0136 in Internet Explorer
Summary
by MITRE
Microsoft Internet Explorer 5.5 on Windows 98 allows remote web pages to cause a denial of service (hang) via extremely long values for form fields such as INPUT and TEXTAREA, which can be automatically filled via Javascript.
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Analysis
by VulDB Data Team • 04/07/2017
The vulnerability described in CVE-2002-0136 represents a classic denial of service flaw affecting Microsoft Internet Explorer 5.5 running on Windows 98 systems. This issue stems from the browser's inadequate handling of excessively long input values in HTML form elements, specifically INPUT and TEXTAREA fields. The vulnerability demonstrates a fundamental lack of input validation and resource management within the browser's rendering engine, creating an exploitable condition that can be triggered through malicious web content.
The technical flaw manifests when remote web pages craft HTML content containing form fields with extremely long string values that exceed normal processing limits. When Internet Explorer attempts to render these oversized input fields, the browser's JavaScript engine and DOM parser become overwhelmed by the excessive data, leading to system resource exhaustion and eventual application hang. This behavior occurs because the browser's internal memory management and string processing functions lack proper bounds checking and overflow protection mechanisms. The vulnerability is particularly dangerous because it can be automatically triggered through JavaScript code execution, eliminating the need for user interaction beyond visiting a malicious webpage.
The operational impact of this vulnerability extends beyond simple browser instability, as it can be leveraged by attackers to disrupt user productivity and potentially create conditions for more sophisticated attacks. Users visiting compromised websites would experience immediate browser hangs, requiring manual intervention to restore normal operation. The vulnerability affects Windows 98 systems specifically, which were widely deployed in enterprise environments during the early 2000s, making this issue particularly concerning for organizations running legacy systems. The automatic filling capability via JavaScript means that exploitation requires no user action beyond navigating to the malicious site, making it an attractive vector for automated attacks.
From a cybersecurity perspective, this vulnerability aligns with CWE-129 Input Validation and Length Checking, as it demonstrates insufficient validation of input parameters. The issue also relates to ATT&CK technique T1499.004, which covers network denial of service attacks, and T1059.007 for the use of JavaScript as an execution method. The flaw represents a precursor to more sophisticated browser-based attacks and highlights the importance of robust input validation in web applications. Organizations should implement immediate mitigations including browser updates, network-level filtering, and user education to prevent exploitation of this vulnerability.
The remediation approach for this vulnerability requires immediate patching of affected Internet Explorer versions, along with system hardening measures to prevent automatic JavaScript execution. Network administrators should consider implementing web content filtering solutions to block malicious pages containing oversized form fields. Additionally, users should be educated about avoiding untrusted websites and maintaining updated browser software. The vulnerability underscores the critical importance of proper resource management in browser implementations and serves as a reminder that even seemingly benign input handling can create significant security risks when not properly validated and bounded.