CVE-2020-6440 in Chrome
Summary
by MITRE
Inappropriate implementation 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 via a crafted Chrome Extension.
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Analysis
by VulDB Data Team • 05/09/2025
The vulnerability identified as CVE-2020-6440 represents a critical security flaw in Google Chrome's extension handling mechanism that existed prior to version 81.0.4044.92. This issue stems from an inadequate implementation approach within the browser's extension framework, creating a pathway for malicious actors to exploit user trust and install harmful extensions that can extract sensitive data. The vulnerability specifically targets the permission model and extension installation process, allowing attackers to bypass normal security boundaries that should protect users from unauthorized data access. The flaw manifests when a user is convinced to install a malicious extension, which then operates with elevated privileges that exceed normal extension capabilities.
This technical weakness operates through a combination of insufficient validation and inadequate sandboxing mechanisms within Chrome's extension architecture. When a malicious extension is installed, the vulnerability allows it to access user data, browsing history, cookies, and potentially sensitive information stored within the browser environment. The implementation flaw creates a gap in Chrome's security model where the extension system fails to properly enforce the principle of least privilege, enabling extensions to perform actions beyond their declared permissions. The vulnerability is particularly dangerous because it leverages social engineering tactics to convince users to install malicious software, making it a prime example of a user-facing attack vector that exploits human psychology alongside technical weaknesses.
The operational impact of CVE-2020-6440 extends beyond simple data theft, as malicious extensions can potentially establish persistent access to user systems and exfiltrate information over time. Attackers can craft extensions that appear legitimate while containing hidden malicious functionality, making detection difficult for both users and security systems. The vulnerability affects the core browser security model and can compromise user privacy, session data, and potentially sensitive business information. This flaw aligns with CWE-284, which addresses improper access control in software implementations, and represents a significant deviation from the expected security boundaries that should protect user data within browser environments.
The exploitation of this vulnerability requires an initial user compromise through social engineering or phishing techniques that convince victims to install malicious extensions. Once installed, the extension can access the user's browsing context and extract sensitive information without proper authorization. This attack vector is particularly concerning because it operates within the legitimate extension ecosystem, making it difficult to distinguish between benign and malicious extensions. The vulnerability's impact is amplified by Chrome's extensive extension marketplace and the trust users place in extension installations, creating a significant security risk for any user running affected Chrome versions.
Organizations and individual users should immediately update to Chrome version 81.0.4044.92 or later to remediate this vulnerability. Security administrators should implement additional monitoring for suspicious extension installations and consider restricting extension installation policies in enterprise environments. The vulnerability demonstrates the importance of maintaining current software versions and implementing layered security approaches that protect against both technical exploits and social engineering attacks. Regular security audits of installed extensions and user education about extension installation risks are essential mitigation strategies that align with established security best practices and help reduce the attack surface for similar vulnerabilities.