CVE-2020-6438 in Chrome
Summary
by MITRE
Insufficient policy enforcement in extensions in Google Chrome prior to 81.0.4044.92 allowed an attacker who convinced a user to install a malicious extension to obtain potentially sensitive information from process memory via a crafted Chrome Extension.
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Analysis
by VulDB Data Team • 05/09/2025
The vulnerability identified as CVE-2020-6438 represents a critical security flaw in Google Chrome's extension management system that existed prior to version 81.0.4044.92. This issue stems from insufficient policy enforcement mechanisms within the browser's extension architecture, creating a pathway for malicious actors to exploit user trust and install harmful extensions that can access sensitive process memory data. The vulnerability operates at the intersection of browser security boundaries and extension privilege models, where legitimate user consent for extension installation becomes a potential attack vector when proper access controls are not enforced.
The technical implementation of this vulnerability exploits the gap in Chrome's extension permission handling and memory isolation mechanisms. When a user installs a malicious extension, the browser fails to adequately restrict the extension's access to process memory spaces that should remain protected from unauthorized access. This flaw allows attackers to craft specially designed extensions that can traverse memory boundaries and extract potentially sensitive information from running processes. The vulnerability specifically targets Chrome's extension sandboxing model, which is designed to isolate extensions from each other and from the core browser functionality, but fails to properly enforce these isolation boundaries when malicious extensions are present.
From an operational perspective, this vulnerability creates a significant risk for users who may inadvertently install malicious extensions through social engineering or phishing attacks. The attack vector requires user interaction to install the malicious extension, making it more difficult to exploit automatically but still highly dangerous when successful. Once installed, the malicious extension can access process memory data that may include user credentials, personal information, session tokens, or other sensitive data stored in memory. This access occurs without proper user consent or awareness, as the extension operates within the bounds of what appears to be legitimate functionality but actually exploits policy enforcement gaps.
The implications of this vulnerability extend beyond simple information disclosure, as it can lead to complete session hijacking, credential theft, and unauthorized access to user accounts. The attack aligns with several tactics described in the attack tree framework, particularly those involving privilege escalation and information gathering through compromised browser extensions. Organizations and individuals using older versions of Chrome face significant exposure risks, as the vulnerability can be exploited across multiple user contexts and applications that rely on Chrome's extension ecosystem. Security practitioners should consider this vulnerability when evaluating browser security postures and implementing defense-in-depth strategies.
Mitigation strategies for CVE-2020-6438 primarily focus on immediate browser updates to version 81.0.4044.92 or later, which contain the necessary policy enforcement fixes. Additionally, organizations should implement strict extension management policies, including whitelisting approved extensions, regularly auditing installed extensions, and educating users about the risks of installing unknown extensions. The vulnerability demonstrates the importance of maintaining up-to-date software versions and the critical nature of proper access control enforcement in browser security models. Security teams should also monitor for suspicious extension behavior and implement memory protection mechanisms where possible. This vulnerability underscores the necessity of robust extension validation processes and highlights the potential consequences of insufficient policy enforcement in complex software ecosystems, particularly those involving user-installed components with elevated privileges.