CVE-2006-6311 in Internet Explorer
Summary
by MITRE
Microsoft Internet Explorer 6.0.2900.2180 allows remote attackers to cause a denial of service via a style attribute in an HTML table tag with a width value that is dynamically calculated using JavaScript.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 05/07/2019
Microsoft Internet Explorer 6.0.2900.2180 contains a vulnerability that enables remote attackers to trigger a denial of service condition through manipulation of HTML table elements. This flaw specifically manifests when processing style attributes within table tags that utilize dynamically calculated JavaScript width values. The vulnerability stems from inadequate input validation and processing of table width specifications that are determined at runtime through JavaScript execution.
The technical implementation of this vulnerability involves the browser's rendering engine encountering a table element with a style attribute containing a width specification that relies on JavaScript calculations. When Internet Explorer attempts to process this dynamic width value, the browser's HTML parser and rendering components fail to properly handle the JavaScript evaluation within the context of table width calculations. This processing failure results in the browser becoming unresponsive or crashing entirely, effectively rendering the application unavailable to users.
From an operational perspective, this vulnerability represents a significant security concern as it allows attackers to remotely disrupt service availability without requiring authentication or privileged access. The attack vector is particularly dangerous because it can be delivered through standard web content, making it easily exploitable via web browsers. The impact extends beyond simple service disruption as it can affect user productivity and potentially provide attackers with opportunities to perform additional malicious activities.
The vulnerability aligns with CWE-129, which addresses improper validation of input boundaries, and relates to ATT&CK technique T1499.004 for network denial of service. This classification indicates that the flaw involves improper handling of input data that should have been validated before processing. The JavaScript-based width calculation creates a scenario where the browser engine cannot properly distinguish between valid and invalid input, leading to resource exhaustion or execution errors.
Mitigation strategies should include immediate deployment of Microsoft security patches and updates that address the specific parsing behavior of table width attributes. Organizations should also implement web application firewalls that can detect and block suspicious table element constructions containing dynamic width specifications. Browser hardening measures such as disabling JavaScript execution for untrusted content and implementing strict content security policies can provide additional protection layers. Network administrators should monitor for unusual browser behavior patterns and implement intrusion detection systems that can identify potential exploitation attempts.
The vulnerability demonstrates the importance of proper input validation in browser rendering engines and highlights the risks associated with complex dynamic content processing. Security teams should conduct regular vulnerability assessments of browser components and ensure that all systems are running patched versions to prevent exploitation. Additionally, user education regarding safe browsing practices and the risks of visiting untrusted websites remains crucial in mitigating potential impacts from such vulnerabilities.