CVE-2011-3004 in Firefox
Summary
by MITRE
The JSSubScriptLoader in Mozilla Firefox 4.x through 6 and SeaMonkey before 2.4 does not properly handle XPCNativeWrappers during calls to the loadSubScript method in an add-on, which makes it easier for remote attackers to gain privileges via a crafted web site that leverages certain unwrapping behavior.
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Analysis
by VulDB Data Team • 11/20/2021
The vulnerability identified as CVE-2011-3004 represents a critical privilege escalation flaw within the JavaScript sandboxing mechanisms of Mozilla Firefox versions 4.x through 6 and SeaMonkey versions prior to 2.4. This issue specifically targets the JSSubScriptLoader component which is responsible for loading JavaScript sub-scripts within browser add-ons and extensions. The flaw exploits weaknesses in how the system handles XPCNativeWrappers during the loadSubScript method execution, creating a pathway for malicious actors to bypass security boundaries that should prevent web content from accessing privileged JavaScript APIs.
The technical implementation of this vulnerability stems from improper handling of XPCNativeWrappers which are used to bridge between JavaScript and native C++ code within Firefox's architecture. When the loadSubScript method processes certain web content, it fails to properly validate or sanitize the unwrapping behavior of these native wrappers, allowing malicious JavaScript code to manipulate the wrapper objects in ways that were not intended by the security model. This improper unwrapping creates a scenario where remote attackers can leverage the flawed behavior to execute privileged operations that should normally be restricted to trusted browser components or add-ons with appropriate permissions.
From an operational perspective, this vulnerability significantly impacts the security posture of affected browsers by enabling remote code execution attacks that can escalate privileges from regular web browsing context to full browser control. Attackers can craft malicious websites that, when visited by users with vulnerable browsers, can exploit the XPCNativeWrappers unwrapping behavior to gain access to sensitive browser functionalities, potentially leading to data theft, browser compromise, or further exploitation of the user's system. The vulnerability is particularly dangerous because it operates within the legitimate add-on loading mechanism, making it difficult to detect through standard security monitoring approaches.
The mitigation strategies for CVE-2011-3004 primarily focus on updating to patched versions of Firefox and SeaMonkey where the JSSubScriptLoader has been properly hardened against the unwrapping behavior exploitation. Organizations should prioritize immediate deployment of security updates and patches, as this vulnerability falls under CWE-264, which addresses permissions, privileges, and access control issues in software systems. The remediation process should also include monitoring for any exploitation attempts and implementing additional security measures such as content security policies and restricted add-on installations to minimize potential attack surface exposure.
This vulnerability aligns with ATT&CK technique T1059.007 which covers JavaScript and VBScript execution, as it allows attackers to execute malicious JavaScript code that leverages browser internals to escalate privileges. The flaw demonstrates the importance of proper sandboxing boundaries in web browsers and highlights how seemingly benign API interactions can create critical security weaknesses when not properly validated against privilege escalation vectors. Security teams should consider this vulnerability as part of broader browser security assessments and ensure comprehensive testing of add-on loading mechanisms to prevent similar issues in other browser components or security frameworks.