CVE-2019-5879 in Chrome
Summary
by MITRE
Insufficient policy enforcement in extensions in Google Chrome prior to 77.0.3865.75 allowed an attacker who convinced a user to install a malicious extension to read local files via a crafted Chrome Extension.
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Analysis
by VulDB Data Team • 02/27/2024
The vulnerability identified as CVE-2019-5879 represents a critical weakness in Google Chrome's extension security model that existed prior to version 77.0.3865.75. This flaw stems from inadequate policy enforcement mechanisms within the browser's extension handling system, creating a pathway for attackers to exploit user trust and install malicious extensions that can bypass normal security boundaries. The vulnerability specifically targets the extension installation and execution process, where proper access controls fail to prevent unauthorized file system access.
The technical implementation of this vulnerability exploits the trust model that exists between users and browser extensions. When users install extensions from the Chrome Web Store or other sources, the browser should enforce strict security policies that prevent extensions from accessing local files without explicit user consent. However, in affected versions, this enforcement mechanism was insufficient, allowing malicious extensions to craft requests that could read local files on the victim's system. The flaw likely resides in the extension permission system where file access permissions are not properly validated or restricted during runtime execution.
The operational impact of this vulnerability extends beyond simple data theft, as it provides attackers with the ability to access sensitive local information including personal documents, configuration files, and potentially system credentials. Attackers could leverage this vulnerability by creating seemingly legitimate extensions that appear trustworthy to users, then use the installed extension to silently access and exfiltrate local files. This creates a sophisticated attack vector that combines social engineering with technical exploitation, making it particularly dangerous in enterprise environments where users may have access to sensitive corporate data.
From a cybersecurity perspective, this vulnerability aligns with CWE-284, which addresses improper access control, and represents a failure in the principle of least privilege enforcement within the browser extension ecosystem. The attack pattern follows typical techniques described in the MITRE ATT&CK framework under the T1176 phase, where adversaries establish persistence through legitimate system processes and user trust. Organizations should consider implementing additional monitoring of extension installations and runtime behaviors as part of their defensive strategies.
Mitigation strategies should focus on immediate browser updates to version 77.0.3865.75 or later, where Google has addressed the insufficient policy enforcement. System administrators should also implement extension management policies that restrict installation sources and monitor for suspicious extension behaviors. Additional protective measures include user education about extension installation risks, implementation of browser security extensions that provide additional access control, and regular security audits of installed extensions. The vulnerability underscores the importance of maintaining current browser versions and implementing comprehensive extension security policies as part of overall cybersecurity frameworks.