CVE-2017-5081 in Chrome
Summary
by MITRE
Lack of verification of an extension's locale folder in Google Chrome prior to 59.0.3071.86 for Mac, Windows, and Linux, and 59.0.3071.92 for Android, allowed an attacker with local write access to modify extensions by modifying extension files.
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Analysis
by VulDB Data Team • 01/04/2023
The vulnerability identified as CVE-2017-5081 represents a critical security flaw in Google Chrome's extension handling mechanism that affected multiple platform versions prior to specific patch releases. This issue stems from insufficient validation of extension locale folders during the browser's extension loading process, creating a pathway for local privilege escalation attacks. The flaw specifically impacts Chrome versions before 59.0.3071.86 on macOS, Windows, and Linux platforms, as well as versions before 59.0.3071.92 on Android devices, making it a widespread concern across the Chrome ecosystem.
The technical root cause of this vulnerability lies in the improper verification of extension locale directories, which are used to store localized resources and user interface elements for browser extensions. When Chrome loads an extension, it typically validates the integrity of extension files to ensure they haven't been tampered with, but this validation process failed to properly check the locale folder structure. This oversight allows an attacker with local write permissions to modify extension files directly, potentially injecting malicious code or altering the extension's behavior without detection. The vulnerability operates at the file system level, leveraging the assumption that extension files are trustworthy once loaded into the browser environment.
The operational impact of CVE-2017-5081 extends beyond simple file modification capabilities, as it enables sophisticated attack vectors that can compromise user data and system integrity. An attacker with local write access can exploit this flaw to replace legitimate extension files with malicious variants, potentially gaining persistent access to user browsing sessions, intercepting sensitive communications, or performing unauthorized actions within the browser environment. The vulnerability is particularly concerning because it requires minimal privileges to exploit, as local write access is often more easily obtained than higher-level system privileges. This makes it a prime target for privilege escalation attacks and persistent threat actors seeking to maintain long-term access to compromised systems.
Mitigation strategies for this vulnerability should focus on immediate patch deployment across all affected Chrome versions, as well as implementing additional security controls to prevent unauthorized file modifications. Organizations should prioritize updating to Chrome versions 59.0.3071.86 or later for desktop platforms and 59.0.3071.92 or later for Android devices. Beyond patching, system administrators should implement file integrity monitoring solutions to detect unauthorized modifications to extension directories, particularly focusing on the locale folder structures that were affected by this vulnerability. The remediation approach aligns with common security practices outlined in the CWE-276 standard for improper file permissions and the ATT&CK framework's privilege escalation techniques, emphasizing the importance of maintaining proper access controls and validating file integrity in browser extension management systems.