CVE-2013-1670 in Firefox
Summary
by MITRE
The Chrome Object Wrapper (COW) implementation in Mozilla Firefox before 21.0, Firefox ESR 17.x before 17.0.6, Thunderbird before 17.0.6, and Thunderbird ESR 17.x before 17.0.6 does not prevent acquisition of chrome privileges during calls to content level constructors, which allows remote attackers to bypass certain read-only restrictions and conduct cross-site scripting (XSS) attacks via a crafted web site.
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Analysis
by VulDB Data Team • 12/23/2024
The vulnerability described in CVE-2013-1670 represents a critical security flaw in the Chrome Object Wrapper implementation within Mozilla Firefox and Thunderbird browsers. This issue stems from insufficient privilege separation mechanisms that allow malicious web content to escalate privileges during constructor calls, effectively undermining the browser's security model. The vulnerability specifically affects versions prior to Firefox 21.0 and Firefox ESR 17.0.6, as well as Thunderbird versions before 17.0.6, making it a widespread concern across multiple Mozilla products. The flaw resides in the browser's ability to properly enforce security boundaries between chrome-level privileged code and content-level untrusted code, creating an avenue for privilege escalation attacks.
The technical implementation of this vulnerability exploits the improper handling of chrome privileges within the browser's object wrapper system. When content-level constructors are invoked, the Chrome Object Wrapper fails to adequately prevent the acquisition of chrome privileges, allowing malicious JavaScript code to access restricted browser functionality. This flaw enables attackers to bypass read-only restrictions that normally protect sensitive chrome-level resources from content-level access. The vulnerability specifically impacts the browser's security model by allowing unprivileged web content to gain access to privileged chrome objects that should only be available to browser internals. This privilege escalation occurs during the execution of content-level constructor calls, where the wrapper mechanism does not properly validate or restrict access to chrome-level resources.
The operational impact of this vulnerability is severe as it enables remote attackers to conduct cross-site scripting attacks with elevated privileges. Attackers can craft malicious websites that exploit this vulnerability to bypass standard security restrictions and execute malicious code with chrome privileges. This allows for sophisticated attacks including but not limited to data exfiltration, browser manipulation, and privilege escalation to full administrative control over the affected browser sessions. The vulnerability essentially provides a pathway for attackers to circumvent the browser's security sandbox, enabling them to access sensitive information and perform actions that should be restricted to trusted browser components. This capability significantly increases the attack surface and potential damage from successful exploitation, as the attacker can leverage chrome-level privileges to bypass multiple layers of browser security.
Mitigation strategies for this vulnerability require immediate patching of affected browser versions to the patched releases that contain proper privilege separation mechanisms. Organizations should ensure that all affected Firefox and Thunderbird installations are updated to versions 21.0 or later for Firefox, 17.0.6 or later for Firefox ESR, and 17.0.6 or later for Thunderbird. Additionally, administrators should implement network-level security controls including web application firewalls and content filtering systems to detect and block known malicious patterns associated with this vulnerability. The fix addresses the underlying issue by strengthening the Chrome Object Wrapper implementation to properly enforce privilege boundaries during constructor calls, preventing content-level code from acquiring chrome privileges. Security monitoring should focus on detecting anomalous browser behavior and privilege escalation attempts that might indicate exploitation of this vulnerability. This vulnerability aligns with CWE-276, which describes improper privilege management, and maps to ATT&CK technique T1059.007 for script-based execution, emphasizing the need for comprehensive browser security updates and monitoring protocols.
The vulnerability demonstrates the critical importance of proper privilege separation in browser security models and highlights the risks associated with complex object wrapper implementations. The flaw represents a fundamental breakdown in the browser's security architecture, where the boundary between privileged and unprivileged code becomes porous under specific conditions. This issue underscores the necessity of rigorous security testing for browser components and the importance of maintaining up-to-date security patches across all browser installations. Organizations should implement automated patch management systems to ensure timely deployment of security updates, as the exploitation of such vulnerabilities can lead to significant security breaches and data loss. The remediation process requires careful verification that all affected products have been properly updated and that no legacy installations remain vulnerable to this privilege escalation attack vector.