CVE-2009-3267 in Internet Explorer
Summary
by MITRE
Microsoft Internet Explorer 6 through 6.0.2900.2180, and 7.0.6000.16711, allows remote attackers to cause a denial of service (CPU consumption) via an automatically submitted form containing a KEYGEN element, a related issue to CVE-2009-1828.
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Analysis
by VulDB Data Team • 08/22/2021
Microsoft Internet Explorer versions 6 through 6.0.2900.2180 and 7.0.6000.16711 contain a vulnerability that enables remote attackers to execute a denial of service attack through excessive cpu consumption. This flaw specifically manifests when the browser encounters an automatically submitted form containing a KEYGEN element, creating a condition that leads to uncontrolled resource utilization. The vulnerability represents a classic example of a resource exhaustion attack where malicious actors can craft web pages that trigger continuous processing loops within the browser's rendering engine.
The technical mechanism behind this vulnerability involves the improper handling of the KEYGEN HTML element within automatic form submission contexts. When Internet Explorer processes such elements, it enters into a recursive or iterative processing state that consumes disproportionate cpu cycles. This behavior stems from inadequate input validation and processing logic within the browser's html parser and form handling components. The vulnerability is categorized under CWE-400 as an unchecked resource consumption issue, where the system fails to properly limit or monitor resource usage during processing of malformed or malicious input.
From an operational perspective, this vulnerability presents significant risks to users who may inadvertently visit compromised websites or receive malicious web content through phishing attacks. The attack requires no special privileges or user interaction beyond normal web browsing, making it particularly dangerous in enterprise environments where users may encounter malicious content through various attack vectors including email attachments, web downloads, or compromised websites. The sustained cpu consumption can lead to complete system unresponsiveness, forcing users to restart their browsers or entire systems to regain normal operation.
The attack pattern aligns with ATT&CK technique T1499.001 for network denial of service attacks, where adversaries leverage browser vulnerabilities to exhaust system resources. This vulnerability demonstrates how seemingly benign html elements can be exploited to create significant operational disruptions. Organizations should consider implementing browser security policies that restrict automatic form submissions and validate html content before rendering. Additionally, keeping Internet Explorer updated to patched versions resolves the underlying issue by implementing proper resource limits and improved input validation mechanisms. Network administrators should monitor for unusual cpu usage patterns that may indicate exploitation attempts, and security teams should prioritize patch management for legacy browser versions that remain in use within enterprise environments.