CVE-2016-1632 in Chrome
Summary
by MITRE
The Extensions subsystem in Google Chrome before 49.0.2623.75 does not properly maintain own properties, which allows remote attackers to bypass intended access restrictions via crafted JavaScript code that triggers an incorrect cast, related to extensions/renderer/v8_helpers.h and gin/converter.h.
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Analysis
by VulDB Data Team • 07/09/2022
The vulnerability identified as CVE-2016-1632 represents a critical access control flaw within Google Chrome's extensions subsystem that existed prior to version 49.0.2623.75. This issue stems from improper handling of object properties within the browser's extension architecture, specifically affecting how the system maintains and validates own properties during JavaScript execution. The flaw manifests in the extensions/renderer/v8_helpers.h and gin/converter.h components, which are integral parts of Chrome's V8 JavaScript engine integration and object conversion mechanisms. The vulnerability allows remote attackers to craft malicious JavaScript code that exploits a type casting error, effectively bypassing intended security restrictions that should prevent unauthorized access to extension resources and capabilities. This represents a significant bypass of Chrome's security model where extension isolation mechanisms fail to properly validate object ownership, creating a pathway for privilege escalation and unauthorized code execution.
The technical exploitation of this vulnerability leverages the improper maintenance of own properties within Chrome's extension system, which operates under the principles of the Common Weakness Enumeration classification CWE-264. The flaw specifically targets the V8 JavaScript engine's handling of object properties and type conversions, where the gin/converter.h component fails to properly validate object ownership before allowing access to extension resources. Attackers can craft JavaScript code that triggers an incorrect cast operation, causing the browser to incorrectly interpret object ownership and access restrictions. This mismanagement of object properties allows malicious code to access extension APIs and resources that should be restricted to legitimate extension contexts. The vulnerability operates at the intersection of JavaScript engine internals and browser security boundaries, making it particularly dangerous as it can be exploited through web-based attacks without requiring local system access. The attack surface includes the browser's renderer process where extension code executes, potentially allowing attackers to access sensitive extension data, manipulate extension behavior, or escalate privileges within the browser sandbox.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential data theft, extension manipulation, and browser compromise. Successful exploitation can allow attackers to access extension-specific resources including user data, browser state information, and extension permissions that should remain isolated from regular web content. This vulnerability affects Chrome's security model by undermining the fundamental principle of extension isolation, which is essential for maintaining browser security boundaries. The flaw can be particularly devastating in environments where users have extensions with elevated privileges, as attackers could potentially access sensitive information or manipulate browser behavior through compromised extension points. The vulnerability's impact is amplified by the fact that it can be triggered through standard web browsing activities, making it an attractive target for phishing campaigns and drive-by attacks. Organizations relying on Chrome-based applications face significant risk as this vulnerability could enable attackers to gain access to enterprise extension data or manipulate browser functionality in ways that could compromise security policies.
Mitigation strategies for CVE-2016-1632 primarily focus on immediate browser updates to versions 49.0.2623.75 and later, which contain the necessary patches to address the improper property handling and casting issues. Security administrators should implement comprehensive browser update policies to ensure all users are protected against this vulnerability, particularly in enterprise environments where multiple browsers may be in use. Additional protective measures include implementing strict content security policies, monitoring for suspicious extension activity, and conducting regular security audits of browser extensions to identify potentially compromised or malicious extensions. The vulnerability's classification under ATT&CK technique T1190 - Exploit Public-Facing Application indicates that organizations should focus on securing browser interfaces and implementing network-based protections against malicious JavaScript execution. Organizations should also consider deploying browser security extensions that can detect and block suspicious JavaScript behavior patterns associated with this type of vulnerability. Regular security training for users about the risks of visiting untrusted websites and the importance of keeping browsers updated remains crucial in preventing exploitation of this and similar vulnerabilities. The patch for this vulnerability specifically addresses the type casting error in the V8 engine's object property handling mechanisms, requiring comprehensive testing to ensure that legitimate extension functionality remains intact while the security flaw is resolved.