CVE-2015-6759 in Chrome
Summary
by MITRE
The shouldTreatAsUniqueOrigin function in platform/weborigin/SecurityOrigin.cpp in Blink, as used in Google Chrome before 46.0.2490.71, does not ensure that the origin of a LocalStorage resource is considered unique, which allows remote attackers to obtain sensitive information via vectors involving a blob: URL.
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Analysis
by VulDB Data Team • 06/21/2022
The vulnerability identified as CVE-2015-6759 resides within the Blink rendering engine's implementation of web origin security mechanisms, specifically in the shouldTreatAsUniqueOrigin function located in platform/weborigin/SecurityOrigin.cpp. This flaw affects Google Chrome versions prior to 46.0.2490.71 and represents a critical security oversight in the browser's cross-origin resource handling capabilities. The vulnerability stems from insufficient validation of LocalStorage origin uniqueness, creating a potential pathway for unauthorized information disclosure.
The technical flaw manifests when the browser fails to properly enforce origin isolation for LocalStorage resources associated with blob: URLs. Blob URLs are special uniform resource identifiers that provide access to binary data objects within web applications, commonly used for file handling and data manipulation operations. When a web application creates a blob URL from user-provided data, the security origin validation should ensure that this resource maintains proper isolation from other origins. However, the flawed implementation in the affected Chrome versions does not adequately verify that the origin associated with LocalStorage operations should be treated as unique, thereby weakening the browser's security boundaries.
This vulnerability enables remote attackers to exploit cross-origin information disclosure scenarios by leveraging the improper handling of blob: URLs in conjunction with LocalStorage mechanisms. An attacker could potentially construct malicious web content that manipulates blob: URLs to access or manipulate LocalStorage data from different origins, effectively bypassing the same-origin policy enforcement that typically protects user data. The impact extends beyond simple information disclosure, as it could potentially allow attackers to access sensitive data that should remain isolated within its original security context, undermining the fundamental security model that web browsers implement to protect user privacy and data integrity.
The operational impact of this vulnerability is significant within the context of modern web security practices and aligns with several ATT&CK framework techniques including T1059 for command and scripting interpreter and T1566 for credential access through social engineering. The vulnerability creates a persistent security risk that could be exploited in various attack scenarios, including man-in-the-middle attacks, cross-site scripting attempts, and data exfiltration operations. Organizations relying on Chrome-based applications face potential exposure to unauthorized data access, especially in environments where sensitive information might be stored in LocalStorage, making this vulnerability particularly concerning for enterprise security postures.
Mitigation strategies for CVE-2015-6759 should prioritize immediate patch deployment to update Chrome browsers to version 46.0.2490.71 or later, which contains the necessary fixes to properly enforce origin uniqueness for LocalStorage resources. Security administrators should also implement additional network-level protections such as Content Security Policy (CSP) headers to limit blob URL usage and restrict LocalStorage access from untrusted origins. The vulnerability demonstrates the importance of proper origin validation in web security frameworks and highlights the need for comprehensive security testing of browser components. Organizations should conduct vulnerability assessments to identify potentially affected systems and review their web application security configurations to minimize the attack surface. This issue also underscores the necessity of maintaining up-to-date browser versions and implementing robust security monitoring to detect and respond to potential exploitation attempts. The vulnerability classification aligns with CWE-200 for exposure of sensitive information and represents a failure in proper input validation and security boundary enforcement within the browser's security architecture.