CVE-2012-5146 in Chrome
Summary
by MITRE
Google Chrome before 24.0.1312.52 allows remote attackers to bypass the Same Origin Policy via a malformed URL.
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Analysis
by VulDB Data Team • 04/22/2021
The vulnerability identified as CVE-2012-5146 represents a critical security flaw in Google Chrome browsers prior to version 24.0.1312.52 that fundamentally undermines the browser's core security model. This issue allows remote attackers to circumvent the Same Origin Policy, which serves as the primary defense mechanism protecting web applications from cross-site scripting and data theft attacks. The Same Origin Policy is a fundamental security principle that restricts how documents or scripts loaded from one origin can interact with resources from another origin, thereby preventing malicious actors from accessing sensitive data across different domains.
The technical implementation of this vulnerability stems from a flaw in Chrome's URL parsing and validation mechanisms. When processing malformed URLs, the browser fails to properly validate the origin of web resources, creating a pathway for attackers to craft specially crafted URLs that bypass the expected security boundaries. This parsing error occurs at the protocol level where Chrome incorrectly interprets certain malformed URL structures, allowing them to be treated as valid cross-origin requests rather than being properly rejected. The flaw specifically affects how Chrome handles URL normalization and origin determination, creating a scenario where attacker-controlled input can manipulate the browser's security context.
The operational impact of this vulnerability is severe and far-reaching, as it enables attackers to perform cross-site scripting attacks, steal session cookies, access user data, and potentially execute arbitrary code within the context of trusted websites. An attacker could craft malicious URLs that appear legitimate to users while simultaneously bypassing the security restrictions that should prevent unauthorized access to sensitive resources. This vulnerability particularly impacts web applications that rely heavily on user authentication, financial transactions, or personal data handling, as it essentially removes the browser's ability to enforce cross-origin restrictions that protect against such attacks. The attack vector is particularly dangerous because it can be delivered through simple web page links or maliciously crafted URLs that users might encounter during normal browsing activities.
This vulnerability aligns with CWE-284, which addresses improper access control, and maps to ATT&CK technique T1059.007 for command and scripting interpreter, as it enables attackers to execute malicious code through browser-based attacks. The flaw demonstrates how protocol-level parsing errors can create security boundaries that should not exist, making it a prime example of how seemingly minor implementation details can have catastrophic security implications. Organizations using vulnerable Chrome versions face significant risk of data breaches, session hijacking, and unauthorized access to sensitive web applications, particularly those handling user credentials, financial information, or confidential data.
The recommended mitigation strategy involves immediate deployment of Chrome version 24.0.1312.52 or later, which includes proper URL validation and normalization that prevents the malformed URL exploitation. Additionally, organizations should implement network-level protections such as web application firewalls and content security policies to add defense-in-depth layers. Browser security updates should be prioritized and deployed immediately, as this vulnerability was actively exploited in the wild. Users should be educated about the importance of keeping their browsers updated and should avoid clicking on suspicious links or visiting untrusted websites. Network administrators should monitor for exploitation attempts and implement logging mechanisms to detect potential attacks targeting this vulnerability. The incident underscores the critical importance of proper input validation and URL parsing in web browser security implementations, highlighting how even minor parsing flaws can create significant security risks that undermine fundamental web security models.