CVE-2012-4184 in Firefox
Summary
by MITRE
The Chrome Object Wrapper (COW) implementation in Mozilla Firefox before 16.0, Firefox ESR 10.x before 10.0.8, Thunderbird before 16.0, Thunderbird ESR 10.x before 10.0.8, and SeaMonkey before 2.13 does not prevent access to properties of a prototype for a standard class, which allows remote attackers to execute arbitrary JavaScript code with chrome privileges via a crafted web site.
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Analysis
by VulDB Data Team • 04/22/2025
The vulnerability described in CVE-2012-4184 represents a critical security flaw in the Chrome Object Wrapper implementation within Mozilla Firefox and related applications. This issue stems from insufficient access control mechanisms that fail to properly restrict property access to prototype objects of standard classes. The vulnerability affects multiple Mozilla products including Firefox, Thunderbird, and SeaMonkey across various version ranges, with specific impacts on versions prior to Firefox 16.0, Firefox ESR 10.x before 10.0.8, Thunderbird 16.0, Thunderbird ESR 10.x before 10.0.8, and SeaMonkey 2.13. The flaw exists in the object model implementation where prototype properties are not adequately protected from unauthorized access, creating a privilege escalation path for remote attackers.
The technical exploitation of this vulnerability occurs through a crafted website that leverages the insufficient access control to manipulate prototype properties of standard JavaScript classes. When a web page attempts to access properties of a prototype object belonging to a standard class, the Chrome Object Wrapper implementation fails to enforce proper security boundaries. This allows attackers to bypass normal JavaScript security restrictions and gain access to chrome privileges, which are typically restricted to privileged browser components. The vulnerability specifically targets the object wrapper mechanism that handles interactions between different security contexts within the browser's JavaScript engine. Attackers can construct malicious web pages that exploit this flaw to execute arbitrary JavaScript code with elevated privileges, effectively breaking down the security sandbox that separates user content from browser internals.
From an operational perspective, this vulnerability presents a severe threat to browser security as it enables remote code execution with chrome privileges, which are the highest level of privileges available within the browser environment. The attack surface is broad since it affects multiple Mozilla products and their respective ESR (Extended Support Release) versions, making it particularly dangerous for enterprise environments that rely on these applications. The vulnerability allows attackers to execute malicious code that could potentially access sensitive user data, modify browser behavior, install malware, or perform other malicious activities that would normally be prevented by the browser's security model. The exploitation requires only a malicious website, making it particularly dangerous for users who browse the internet without additional security measures. This vulnerability directly impacts the principle of least privilege and breaks down the security boundaries that protect the browser's core functionality from user-controlled content.
The mitigation strategies for CVE-2012-4184 primarily involve updating to patched versions of the affected software, with Mozilla releasing updates that properly enforce access control for prototype properties. Organizations should prioritize immediate deployment of security patches for Firefox 16.0, Thunderbird 16.0, and SeaMonkey 2.13, along with their respective ESR versions. Additionally, browser security configurations can be enhanced by implementing content security policies, disabling unnecessary JavaScript features, and employing browser hardening techniques. The vulnerability aligns with CWE-284 (Improper Access Control) and can be mapped to ATT&CK technique T1059.007 (Command and Scripting Interpreter: JavaScript) in the context of privilege escalation. Organizations should also consider implementing network-level protections such as web application firewalls and monitoring for suspicious JavaScript behavior to detect potential exploitation attempts. Regular security assessments and vulnerability scanning should be conducted to ensure all affected systems are properly patched and that no legacy installations remain vulnerable to this attack vector.