CVE-2011-3887 in Chrome
Summary
by MITRE
Google Chrome before 15.0.874.102 does not properly handle javascript: URLs, which allows remote attackers to bypass intended access restrictions and read cookies via unspecified vectors.
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Analysis
by VulDB Data Team • 11/24/2021
The vulnerability identified as CVE-2011-3887 represents a critical security flaw in Google Chrome versions prior to 15.0.874.102 that stems from improper handling of javascript: URLs within the browser's security model. This weakness specifically affects the browser's ability to properly enforce access restrictions when processing javascript: protocol URLs, creating a pathway for remote attackers to bypass intended security controls. The flaw operates at the intersection of browser security architecture and URL handling mechanisms, where the application fails to adequately validate or sanitize javascript: URLs before executing them within the context of web pages. This vulnerability is particularly concerning because it directly impacts the browser's cookie management system, potentially allowing unauthorized access to sensitive session data.
The technical implementation of this vulnerability involves the browser's failure to properly isolate javascript: URLs from the regular web page execution environment. When Chrome processes a javascript: URL, it should enforce strict security boundaries to prevent malicious code from accessing or manipulating cookies that belong to different domains or have specific security attributes. However, the flaw in the affected versions allows attackers to craft javascript: URLs that can traverse these security boundaries, enabling them to read cookies that should otherwise be protected by the Same-Origin Policy. This issue falls under the CWE-20 category of Improper Input Validation, specifically manifesting as a failure in URL scheme handling that creates an unexpected execution path for javascript code. The vulnerability's impact extends beyond simple cookie reading to potentially compromise user sessions and access sensitive data that relies on cookie-based authentication mechanisms.
From an operational perspective, this vulnerability creates significant risk for users of affected Chrome versions as it allows remote attackers to perform session hijacking attacks without requiring local system access or complex exploitation techniques. Attackers can leverage this flaw by embedding malicious javascript: URLs within web pages or through social engineering campaigns, where unsuspecting users might inadvertently trigger the execution of code that reads cookies from other domains. The attack vector typically involves crafting specially formatted javascript: URLs that exploit the browser's insufficient validation logic to access cookie data that should be restricted. This vulnerability directly impacts the browser's ability to maintain secure session boundaries and can lead to unauthorized access to user accounts, particularly those relying on cookie-based authentication systems. The flaw essentially undermines the browser's security model by allowing code execution that bypasses fundamental web security principles.
The mitigation strategy for CVE-2011-3887 requires immediate upgrading to Chrome version 15.0.874.102 or later, which contains the necessary patches to properly handle javascript: URLs and enforce appropriate security boundaries. Organizations should also implement additional protective measures including regular browser updates, deployment of security policies that restrict javascript execution in sensitive contexts, and monitoring for suspicious URL patterns in web traffic. Network administrators can deploy web application firewalls or content filtering solutions that detect and block malicious javascript: URL patterns. From a defensive standpoint, this vulnerability demonstrates the importance of maintaining up-to-date browser software and implementing layered security approaches that protect against browser-based attacks. The fix implemented in Chrome 15.0.874.102 addresses the core issue by strengthening the validation and sanitization of javascript: URLs, ensuring that these protocol handlers properly enforce security boundaries and prevent unauthorized cookie access. This remediation aligns with the ATT&CK framework's mitigation strategies for browser exploitation techniques, emphasizing the need for proper input validation and secure coding practices in web browser implementations.