CVE-2021-30574 in Chrome
Summary
by MITRE • 08/04/2021
Use after free in protocol handling in Google Chrome prior to 92.0.4515.107 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.
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Analysis
by VulDB Data Team • 08/07/2021
The vulnerability identified as CVE-2021-30574 represents a critical use-after-free condition within Google Chrome's protocol handling mechanisms that existed in versions prior to 92.0.4515.107. This flaw resides in the browser's memory management system where an object is freed from memory but references to that object persist, creating a dangerous scenario where subsequent operations attempt to access deallocated memory regions. The issue manifests specifically during the processing of crafted HTML content, making it particularly dangerous in web-based attack scenarios where remote adversaries can leverage this vulnerability without requiring user interaction beyond visiting a malicious webpage.
The technical implementation of this vulnerability stems from improper memory management within Chrome's rendering engine, where protocol handlers fail to properly track object lifecycles during HTML parsing operations. When processing specially crafted HTML elements, the browser's memory allocator may release memory occupied by certain objects while the execution context still maintains references to those locations. This creates a scenario where an attacker can manipulate the heap layout to overwrite critical memory segments or inject malicious code into the freed memory space. The vulnerability is classified under CWE-416 as a use-after-free error, which is a well-documented pattern that has historically led to remote code execution exploits due to the potential for heap corruption and arbitrary code execution.
From an operational standpoint, this vulnerability presents a significant risk to users of affected Chrome versions as it enables remote code execution without user interaction, making it particularly dangerous in phishing campaigns and drive-by download scenarios. The attack vector requires only that a user visits a malicious website containing crafted HTML content, which then triggers the memory corruption during normal browsing operations. Security researchers have noted that exploitation of this vulnerability typically involves sophisticated techniques to achieve reliable remote code execution, including heap spraying and precise memory layout manipulation. The vulnerability affects all platforms where Chrome is deployed, including Windows, macOS, Linux, and mobile operating systems, making it a widespread concern for enterprise security teams managing browser-based attack surfaces.
Organizations and individuals should immediately update to Chrome version 92.0.4515.107 or later to mitigate this vulnerability, as Google has addressed the issue through memory management improvements and enhanced object lifecycle tracking within the browser's protocol handling components. Additional mitigations include implementing web application firewalls that can detect and block malicious HTML content, deploying browser security extensions that enhance memory protection mechanisms, and configuring network-level controls to restrict access to known malicious domains. The vulnerability demonstrates the importance of continuous security monitoring and rapid patch deployment, as it aligns with ATT&CK technique T1059.007 for command and scripting interpreter and T1071.004 for application layer protocol, highlighting the need for comprehensive security controls that address both endpoint protection and network-based defenses. Security teams should also consider implementing automated vulnerability scanning tools that can detect the presence of this vulnerability in their environments and ensure proper patch management procedures are in place to prevent exploitation.