CVE-2018-6095 in Chrome
Summary
by MITRE
Inappropriate dismissal of file picker on keyboard events in Blink in Google Chrome prior to 66.0.3359.106 allowed a remote attacker to read local files via a crafted HTML page.
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Analysis
by VulDB Data Team • 06/13/2023
The vulnerability identified as CVE-2018-6095 represents a critical security flaw within the Blink rendering engine of Google Chrome browsers. This issue stems from an improper handling of file picker dismissal mechanisms when keyboard events occur, creating a significant vector for remote code execution and data exfiltration. The flaw existed in Chrome versions prior to 66.0.3359.106, leaving millions of users exposed to potential exploitation by malicious actors. The vulnerability specifically targets the interaction between user interface elements and keyboard input handling within the browser's file selection functionality, demonstrating a fundamental breakdown in input validation and security boundary enforcement.
Technical analysis reveals that the flaw operates through a race condition or improper state management within the file picker component of Blink. When users interact with file selection dialogs using keyboard inputs, the browser fails to properly validate or dismiss the file picker interface, allowing crafted HTML pages to manipulate the dismissal process. This creates an unintended code path where remote attackers can construct malicious web pages that, when loaded in a vulnerable browser, can trigger the file picker and subsequently access local file system resources. The vulnerability essentially bypasses normal security restrictions that should prevent web pages from directly accessing local files without explicit user consent.
The operational impact of CVE-2018-6095 extends far beyond simple information disclosure, as it enables attackers to perform unauthorized file system operations and potentially extract sensitive data from compromised systems. Attackers can craft HTML pages that, when visited by victims, automatically trigger file picker dialogs and then exploit the improper dismissal handling to read arbitrary files from the local system. This capability aligns with attack patterns described in the MITRE ATT&CK framework under the T1059.001 technique for command and scripting interpreter, as well as T1074.001 for data staging through local file system access. The vulnerability essentially provides a pathway for attackers to circumvent browser sandboxing mechanisms and gain unauthorized access to local resources that should remain protected from web-based access attempts.
Security professionals should note that this vulnerability demonstrates the critical importance of proper input validation and state management in browser components. The issue reflects weaknesses commonly associated with CWE-20, which addresses improper input validation, and CWE-352, concerning cross-site request forgery. Organizations should prioritize immediate patching of affected Chrome installations to prevent exploitation attempts, while also implementing network monitoring to detect potential exploitation attempts. Browser vendors and security teams should also consider implementing additional layers of protection around file system access points and keyboard event handling to prevent similar issues from occurring in future implementations. The vulnerability serves as a reminder of the complex security challenges inherent in modern browser architectures where user interface components must balance usability with security isolation.