CVE-2021-30576 in Chrome
Summary
by MITRE • 08/04/2021
Use after free in DevTools in Google Chrome prior to 92.0.4515.107 allowed an attacker who convinced a user to install a malicious extension to potentially exploit heap corruption via a crafted HTML page.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 08/07/2021
The vulnerability identified as CVE-2021-30576 represents a critical use-after-free condition within the DevTools component of Google Chrome browsers. This flaw exists in versions prior to 92.0.4515.107 and creates a significant security risk that can be exploited through malicious extension installation combined with crafted HTML page delivery. The vulnerability stems from improper memory management practices within the browser's developer tools framework, specifically when handling certain objects that are freed from memory but subsequently accessed by malicious code. The use-after-free condition occurs when the browser attempts to access memory that has already been deallocated, creating opportunities for heap corruption and potential arbitrary code execution.
The technical exploitation of this vulnerability requires an attacker to first convince a user to install a malicious browser extension, which then serves as a delivery mechanism for the crafted HTML payload. The DevTools component in Chrome provides extensive debugging and development capabilities that are typically available to legitimate users, but this functionality can be abused when combined with memory corruption vulnerabilities. The flaw manifests in the way Chrome manages object lifecycles within the debugging environment, where objects allocated for debugging purposes are not properly tracked or validated before deallocation. This creates a window of opportunity where attacker-controlled code can manipulate the freed memory regions and potentially redirect execution flow or corrupt critical data structures.
The operational impact of CVE-2021-30576 extends beyond simple browser compromise, as it can lead to complete system takeover when exploited successfully. The vulnerability aligns with CWE-416, which specifically addresses use-after-free conditions in software implementations, and follows attack patterns consistent with those documented in the MITRE ATT&CK framework under techniques related to privilege escalation and code execution. Successful exploitation could allow an attacker to bypass standard browser security mechanisms, access user data, perform unauthorized actions, or establish persistent backdoors. The attack vector is particularly concerning because it leverages the legitimate DevTools functionality that many users may have enabled, making the exploitation more likely to succeed in real-world scenarios.
Mitigation strategies for this vulnerability require immediate browser updates to version 92.0.4515.107 or later, which contains the necessary memory management fixes and proper object lifecycle handling. Organizations should implement comprehensive patch management procedures to ensure all Chrome installations are updated promptly, particularly in enterprise environments where browser security is critical. Additionally, users should be educated about the risks of installing unknown browser extensions and the importance of only downloading extensions from trusted sources such as the official Chrome Web Store. Security administrators should monitor for any attempts to install suspicious extensions and consider implementing browser security policies that restrict extension installation or require administrator approval for new extensions. The vulnerability demonstrates the importance of proper memory management in browser components and highlights how seemingly benign debugging features can become attack surfaces when not properly secured against memory corruption attacks.