CVE-2020-6385 in Chrome
Summary
by MITRE
Insufficient policy enforcement in storage in Google Chrome prior to 80.0.3987.87 allowed a remote attacker to bypass site isolation via a crafted HTML page.
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Analysis
by VulDB Data Team • 05/10/2025
The vulnerability identified as CVE-2020-6385 represents a critical security flaw in Google Chrome's site isolation implementation that existed prior to version 80.0.3987.87. This issue falls under the broader category of insufficient policy enforcement within the browser's storage management system, creating a pathway for remote attackers to circumvent fundamental security boundaries that separate different websites and their respective data contexts. The flaw specifically targets Chrome's site isolation mechanism, which was designed to prevent malicious websites from accessing data from other origins through isolation of processes and memory spaces. This vulnerability operates at the intersection of multiple security domains including web browser architecture, memory management, and cross-origin resource protection.
The technical root cause of this vulnerability stems from inadequate enforcement of security policies within Chrome's storage subsystem, particularly when handling crafted HTML pages that exploit the gap between intended isolation boundaries and actual implementation. Attackers can construct malicious web pages that manipulate the browser's storage handling mechanisms to bypass the site isolation protections that should normally prevent one website from accessing another website's storage resources. This flaw allows for cross-site data leakage and potential information disclosure attacks where sensitive data from one origin can be accessed by another. The vulnerability demonstrates a classic case of incomplete input validation and insufficient boundary checking within the browser's security architecture, which aligns with CWE-691 - Insufficient Control Flow Management and CWE-284 - Improper Access Control patterns.
The operational impact of CVE-2020-6385 is significant as it undermines one of Chrome's core security features designed to protect users from cross-site scripting attacks and data leakage. Remote attackers can exploit this vulnerability by simply delivering a malicious HTML page to a victim, requiring no special privileges or user interaction beyond visiting the compromised site. The attack vector operates entirely through standard web browsing channels, making it particularly dangerous as it can be executed against any user who visits the malicious page without requiring additional attack surface exploitation. This vulnerability creates persistent access to storage data that should normally be isolated, potentially enabling attackers to gather sensitive information including cookies, local storage data, session information, and other browser-stored resources from different origins.
Mitigation strategies for this vulnerability require immediate patching of Chrome browsers to version 80.0.3987.87 or later, where Google implemented proper policy enforcement mechanisms to address the storage isolation gap. Organizations should also implement additional protective measures including browser hardening configurations, content security policies, and regular security assessments of web applications. Network-level protections such as web application firewalls and intrusion detection systems can help detect and block malicious web content attempts, though these measures provide only secondary protection. The vulnerability highlights the importance of maintaining up-to-date browser software and following security best practices, as it represents a failure in Chrome's security architecture that could enable more sophisticated attacks. Security teams should also consider implementing monitoring for unusual storage access patterns and cross-origin resource access attempts that might indicate exploitation attempts. This vulnerability demonstrates the critical need for continuous security testing and validation of browser security features, particularly those related to process isolation and memory management, which are fundamental to modern web browser security models and align with attack patterns documented in the MITRE ATT&CK framework under the category of privilege escalation and credential access.