CVE-2009-2764 in Windows
Summary
by MITRE
Microsoft Internet Explorer 8.0.7100.0 on Windows 7 RC on the x64 platform allows remote attackers to cause a denial of service (application crash) via a certain DIV element in conjunction with SCRIPT elements that have empty contents and no reference to a valid external script location.
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Analysis
by VulDB Data Team • 12/08/2024
The vulnerability described in CVE-2009-2764 represents a denial of service flaw within Microsoft Internet Explorer 8.0.7100.0 running on Windows 7 Release Candidate systems with x64 architecture. This issue stems from improper handling of specific HTML element combinations that trigger application instability. The flaw manifests when the browser encounters a DIV element paired with SCRIPT elements containing empty content and no valid external script references. Such malformed HTML constructs cause the browser to crash during rendering or execution phases, effectively disrupting user access to web content and potentially enabling attackers to exploit this weakness for more severe attacks.
The technical root cause of this vulnerability lies in the browser's HTML parsing and rendering engine's inadequate validation of SCRIPT element attributes and content structure. When Internet Explorer processes a DIV element containing SCRIPT tags with empty inner content and no src attribute pointing to valid external resources, the engine fails to properly handle the malformed structure, leading to memory corruption or execution flow disruption. This behavior aligns with CWE-129, which addresses improper validation of input, and CWE-170, concerning improper handling of potentially dangerous input. The vulnerability specifically demonstrates how malformed HTML can cause application instability through improper resource management and memory handling during parsing operations.
From an operational perspective, this vulnerability presents significant risks to both individual users and enterprise environments. The denial of service condition can be exploited remotely by attackers who craft malicious web pages containing the specific HTML structure that triggers the crash. Users accessing compromised websites would experience unexpected browser crashes, potentially disrupting productivity and creating opportunities for more sophisticated attacks. The impact extends beyond simple disruption as attackers could potentially leverage this weakness as a precursor to more serious exploits or use it to target specific user populations. This vulnerability falls under ATT&CK technique T1499.004, which covers network denial of service attacks, and demonstrates how web browser vulnerabilities can be weaponized for broader cyber operations.
The mitigation strategies for this vulnerability primarily involve applying Microsoft's security patches and updates to Internet Explorer 8.0.7100.0, as well as implementing proper input validation on web servers to prevent malicious HTML content from being served to users. Organizations should also consider deploying web application firewalls and content filtering solutions to detect and block potentially malicious HTML constructs. Additionally, browser hardening practices including disabling unnecessary scripting capabilities and implementing strict content security policies can reduce the attack surface. Users should maintain updated software versions and avoid accessing untrusted websites that might contain malicious HTML content designed to exploit this specific vulnerability. The remediation process should include comprehensive testing to ensure that the patch does not introduce compatibility issues with legitimate web applications while effectively addressing the underlying parsing flaw that allows the denial of service condition to occur.