CVE-2020-6492 in Chrome
Summary
by MITRE • 11/03/2021
Use after free in ANGLE in Google Chrome prior to 83.0.4103.97 allowed a remote attacker to potentially perform a sandbox escape via a crafted HTML page.
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Analysis
by VulDB Data Team • 11/06/2021
The vulnerability CVE-2020-6492 represents a critical use-after-free flaw in the ANGLE graphics library component that forms part of Google Chrome's rendering architecture. This vulnerability exists within the handling of graphics resources and specifically affects Chrome versions prior to 83.0.4103.97. The ANGLE library serves as a Direct3D to OpenGL translation layer that enables Chrome to render graphics content on various operating systems, making it a fundamental component in the browser's graphics processing pipeline. When a remote attacker crafts a malicious HTML page containing specific graphics operations, the flaw can be exploited to manipulate memory that has already been freed, creating opportunities for arbitrary code execution.
The technical implementation of this vulnerability stems from improper memory management within the ANGLE component's graphics resource handling mechanisms. During normal operation, Chrome allocates and manages graphics resources such as textures, buffers, and shaders through ANGLE's memory management system. However, under specific conditions involving crafted HTML content, the system fails to properly track resource lifecycles, leading to scenarios where memory locations are freed but still referenced by subsequent operations. This use-after-free condition creates a memory corruption vulnerability that can be leveraged by attackers to execute malicious code with the privileges of the Chrome process. The flaw particularly manifests when processing complex graphics operations that involve multiple resource allocations and deallocations, where race conditions or improper reference counting allow freed memory to be accessed.
The operational impact of CVE-2020-6492 extends beyond typical browser exploitation scenarios due to its potential for sandbox escape. Modern browsers implement sandboxing mechanisms to isolate the rendering process from the underlying operating system, preventing attackers from directly accessing system resources. However, successful exploitation of this vulnerability could potentially bypass these sandbox protections, allowing attackers to execute code with elevated privileges. This represents a significant escalation from typical browser-based attacks, as it could enable attackers to gain access to sensitive system resources, read files, modify data, or even install persistent malware on affected systems. The vulnerability affects a wide range of operating systems including Windows, macOS, and Linux, where Chrome is deployed, making it particularly concerning for enterprise environments and individual users alike.
The exploitation of this vulnerability aligns with several ATT&CK techniques including T1059 for command execution and T1068 for privilege escalation. From a CWE perspective, this vulnerability maps to CWE-416 which describes use-after-free conditions, and potentially CWE-787 for out-of-bounds write operations that may occur during memory corruption. Organizations should prioritize immediate patching of Chrome installations to version 83.0.4103.97 or later, as this represents the first fixed release addressing the memory management flaw. Additional mitigations include enabling Chrome's built-in security features such as site isolation, sandboxing, and automatic updates to ensure timely protection against similar vulnerabilities. Network administrators should also consider implementing web content filtering solutions and monitoring for suspicious HTML content that may attempt to trigger this or related graphics rendering vulnerabilities. The vulnerability demonstrates the critical importance of proper memory management in graphics libraries and highlights how seemingly isolated component flaws can have significant implications for overall browser security architecture.