CVE-2019-5850 in Chrome
Summary
by MITRE
Use after free in offline mode in Google Chrome prior to 76.0.3809.87 allowed a remote attacker who had compromised the renderer process to potentially perform a sandbox escape via a crafted HTML page.
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Analysis
by VulDB Data Team • 02/27/2024
The vulnerability identified as CVE-2019-5850 represents a critical use-after-free condition that existed in Google Chrome's offline mode functionality prior to version 76.0.3809.87. This flaw specifically manifested within the renderer process of the browser, creating a pathway for remote attackers who had already compromised this process to potentially escape the sandbox protection mechanisms that typically isolate browser components from the underlying operating system. The issue stems from improper memory management where freed memory locations are accessed after being deallocated, a classic vulnerability pattern that can lead to arbitrary code execution when exploited correctly.
The technical implementation of this vulnerability involves the interaction between Chrome's offline mode handling and memory management routines within the renderer process. When processing crafted HTML content in offline scenarios, the browser fails to properly validate memory references, allowing freed memory to be accessed and potentially overwritten by malicious code. This particular flaw operates under the Common Weakness Enumeration category of CWE-416, which specifically addresses use-after-free vulnerabilities where software accesses memory after it has been freed, creating potential for exploitation. The vulnerability's impact is particularly severe because it leverages an attacker's existing compromise of the renderer process, eliminating the need for additional initial access vectors.
From an operational perspective, this vulnerability creates a significant escalation path for attackers who have already achieved a foothold within Chrome's sandboxed environment. The sandbox escape capability means that an attacker who has compromised the renderer process could potentially gain access to system resources and privileges beyond what the browser's security model intends to permit. This vulnerability directly relates to the ATT&CK framework's technique T1055, which covers process injection and memory manipulation techniques, and T1074, which addresses data staging through compromised processes. The exploitation of this vulnerability essentially undermines the fundamental security boundary that separates the browser's rendering engine from the underlying operating system.
The remediation approach for CVE-2019-5850 requires immediate updating of Chrome to version 76.0.3809.87 or later, which includes patches that address the improper memory management in offline mode handling. Organizations should implement comprehensive browser update policies and consider automated patch management systems to ensure timely deployment of security fixes. Additionally, security teams should monitor for any exploitation attempts through network traffic analysis and endpoint detection systems, particularly focusing on unusual memory access patterns or sandbox escape behaviors. The vulnerability demonstrates the critical importance of maintaining up-to-date browser security implementations and highlights how seemingly isolated process-level flaws can create significant system-wide security implications when combined with existing compromise scenarios.