CVE-2011-4682 in Web Browser
Summary
by MITRE
The JavaScript engine in Opera before 11.60 does not properly implement the in operator, which allows remote attackers to bypass the Same Origin Policy via vectors related to variables on different web sites.
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Analysis
by VulDB Data Team • 11/27/2021
The vulnerability identified as CVE-2011-4682 resides within the JavaScript engine of Opera web browser versions prior to 11.60, specifically targeting the improper implementation of the JavaScript in operator. This flaw represents a critical security weakness that undermines the fundamental Same Origin Policy (SOP) enforcement mechanism that governs web browser security. The in operator in JavaScript is designed to test whether an object has a specified property, including properties inherited through the prototype chain, and its incorrect implementation creates exploitable conditions that allow malicious actors to circumvent browser security boundaries.
The technical flaw manifests when the JavaScript engine fails to properly validate property access across different origins, enabling attackers to craft malicious scripts that can probe and access properties of objects from different domains. This vulnerability operates through a sophisticated manipulation of the JavaScript engine's property resolution mechanisms, allowing remote attackers to perform cross-origin information disclosure attacks. The flaw essentially creates a pathway through which variables and properties from different websites can be accessed without proper authorization, effectively breaking down the isolation that separate web origins should maintain.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with the capability to perform advanced persistent reconnaissance against users' browsing sessions. Attackers can leverage this weakness to discover the presence of specific properties or methods on objects from other origins, potentially leading to the exposure of sensitive data or the identification of security-relevant implementation details. This capability significantly undermines the browser's security model and can be exploited in conjunction with other vulnerabilities to create more sophisticated attack vectors. The vulnerability affects the core JavaScript engine functionality and represents a fundamental flaw in how the browser handles cross-origin property access, making it particularly dangerous as it operates at the level of the language interpreter itself.
Mitigation strategies for CVE-2011-4682 require immediate browser updates to Opera version 11.60 or later, which contain the necessary fixes for the JavaScript engine's in operator implementation. Security administrators should also implement network-level protections such as content security policies and strict origin validation mechanisms to limit the potential impact of exploitation attempts. The vulnerability aligns with CWE-284 Access Control Issues and can be categorized under ATT&CK technique T1059.007 Command and Scripting Interpreter JavaScript, demonstrating how browser-based vulnerabilities can enable persistent access to user sessions and sensitive information. Organizations should conduct thorough security assessments to identify any potential exploitation attempts and ensure that all users are updated to secure browser versions to prevent unauthorized cross-origin data access.