CVE-2018-17462 in Chrome
Summary
by MITRE
Incorrect refcounting in AppCache in Google Chrome prior to 70.0.3538.67 allowed a remote attacker to perform a sandbox escape via a crafted HTML page.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 06/06/2023
The vulnerability identified as CVE-2018-17462 represents a critical sandbox escape flaw within Google Chrome's Application Cache implementation that existed prior to version 70.0.3538.67. This issue stems from improper reference counting mechanisms within the browser's application cache system, which governs how web applications store and manage cached resources for offline access. The flaw specifically affects Chrome's security model where the application cache operates within a restricted sandbox environment designed to isolate potentially malicious content from the underlying operating system and other browser processes. The incorrect refcounting behavior creates a scenario where memory management operations can be manipulated to bypass these security boundaries.
The technical exploitation of this vulnerability occurs through a carefully crafted HTML page that leverages the flawed reference counting logic to manipulate the application cache's internal state. When Chrome processes such malicious content, the improper refcounting causes memory objects associated with the cache to be prematurely freed or improperly managed, creating a condition that allows an attacker to execute code outside the intended sandbox boundaries. This type of vulnerability falls under the CWE-129 weakness category, specifically addressing improper handling of reference counts and memory management within browser components. The flaw enables attackers to escalate privileges from the restricted browser sandbox to potentially full system access, making it particularly dangerous for user environments.
Operationally, this vulnerability poses significant risks to web browsing security as it allows remote attackers to execute arbitrary code on affected systems without requiring user interaction beyond visiting a malicious webpage. The sandbox escape capability means that an attacker could potentially access sensitive data, modify system files, or establish persistent access to the compromised machine. The vulnerability impacts all users running Chrome versions before 70.0.3538.67, making it a widespread concern across various operating systems and deployment scenarios. Security researchers have documented that this flaw could be exploited in conjunction with other techniques to create more sophisticated attacks, as the ability to escape browser sandboxes often serves as a foundational step for additional exploitation vectors.
Mitigation strategies for CVE-2018-17462 primarily focus on immediate remediation through browser updates to version 70.0.3538.67 or later, which contains the necessary patches to correct the reference counting logic in the application cache implementation. Organizations should implement comprehensive patch management procedures to ensure all Chrome installations are updated promptly. Additional defensive measures include implementing content security policies that restrict access to potentially malicious resources, deploying web application firewalls that can detect and block suspicious HTML content patterns, and utilizing browser hardening techniques that further restrict application cache functionality. The vulnerability demonstrates the importance of proper memory management in browser security architectures and highlights the need for continuous security auditing of core browser components. Security teams should also consider implementing monitoring solutions that can detect unusual patterns in application cache operations, as these may indicate exploitation attempts. The ATT&CK framework categorizes this vulnerability under the technique of privilege escalation through sandbox escapes, specifically targeting the browser's security model to gain elevated system access.