CVE-2020-6402 in Chrome
Summary
by MITRE
Insufficient policy enforcement in downloads in Google Chrome on OS X prior to 80.0.3987.87 allowed an attacker who convinced a user to install a malicious extension to execute arbitrary code via a crafted Chrome Extension.
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Analysis
by VulDB Data Team • 05/10/2025
The vulnerability identified as CVE-2020-6402 represents a critical policy enforcement flaw within Google Chrome's extension management system on macOS operating systems. This weakness existed in Chrome versions prior to 80.0.3987.87 and fundamentally compromised the browser's security model by allowing malicious actors to bypass download restrictions through crafted extension packages. The vulnerability stems from insufficient validation mechanisms that should have prevented unauthorized code execution during the extension installation process, creating a pathway for privilege escalation attacks.
The technical flaw manifests through a combination of inadequate input sanitization and weak access control measures within Chrome's extension handling subsystem. When users attempted to install malicious extensions, the browser failed to properly validate the extension's integrity and intended functionality, allowing attackers to package malicious code within seemingly legitimate extension bundles. This weakness aligns with CWE-284, which addresses improper access control, and specifically targets the insufficient enforcement of security policies during software installation processes. The vulnerability operates at the intersection of browser security architecture and extension management protocols, where the expected security boundaries were not properly maintained during the download and installation phases.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with a persistent foothold within user environments through browser-based attack vectors. Once a user installs a malicious extension, the attacker gains the ability to execute arbitrary code with the privileges of the browser process, potentially leading to data exfiltration, system compromise, or further lateral movement within the network. This attack vector leverages social engineering tactics to convince users to install malicious extensions, making it particularly dangerous in enterprise environments where user education and awareness may be insufficient. The vulnerability's exploitation aligns with ATT&CK technique T1176, which describes the use of browser extensions for persistence and privilege escalation.
Mitigation strategies for CVE-2020-6402 primarily focus on immediate system updates and enhanced security monitoring. Organizations should prioritize updating all Chrome installations to version 80.0.3987.87 or later, as this release includes the necessary policy enforcement improvements. Additionally, implementing browser security policies that restrict extension installation from untrusted sources, enabling strict extension verification mechanisms, and conducting regular security audits of installed extensions can significantly reduce the risk of exploitation. Security teams should also monitor for suspicious extension installations and implement network-level controls to detect and block malicious extension downloads. The vulnerability highlights the importance of maintaining up-to-date software and demonstrates how seemingly minor policy enforcement gaps can create significant security risks in browser environments.