CVE-2021-30567 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 open DevTools to potentially exploit heap corruption via specific user gesture.
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Analysis
by VulDB Data Team • 08/07/2021
The vulnerability identified as CVE-2021-30567 represents a critical use-after-free flaw within the Developer Tools component of Google Chrome browsers. This issue affects versions prior to 92.0.4515.107 and demonstrates a classic memory safety vulnerability that can be exploited through user interaction. The flaw occurs when the DevTools functionality handles specific user gestures, creating conditions where freed memory objects can be accessed again, potentially leading to heap corruption. The vulnerability is particularly concerning because it requires only a user to open DevTools, making it exploitable through social engineering or phishing techniques. Attackers can leverage this weakness to execute arbitrary code on the target system, potentially leading to full system compromise. The use-after-free condition arises from improper memory management within the DevTools module, where object references are not properly invalidated after memory deallocation, allowing subsequent access to freed memory regions.
The technical implementation of this vulnerability involves the interaction between user gestures and the DevTools component's memory management system. When users interact with specific elements within DevTools, the underlying code executes operations that trigger memory deallocation followed by subsequent access to the same memory locations. This pattern creates a window where malicious code can manipulate the heap structure, potentially overwriting critical memory regions or injecting malicious payloads. The vulnerability's exploitation requires the victim to actively engage with DevTools, typically through user gestures such as clicking or interacting with specific UI elements. This makes the attack surface more limited compared to fully automated exploits but still represents a significant risk given the widespread use of browser developer tools. The heap corruption resulting from this flaw can manifest in various ways including information disclosure, denial of service, or more severe remote code execution depending on the exploitation context and target system configuration.
The operational impact of CVE-2021-30567 extends beyond simple browser compromise as it represents a potential pathway for attackers to escalate privileges and gain deeper system access. The vulnerability's reliance on user interaction makes it particularly dangerous in targeted attacks where social engineering can be combined with the technical exploit to achieve successful compromise. Security researchers have classified this issue under CWE-416, which specifically addresses use-after-free vulnerabilities in software systems, highlighting the fundamental memory management flaw that enables the exploitation. The attack vector follows typical patterns described in the ATT&CK framework under T1059 for command and scripting interpreter and T1068 for exploit for privilege escalation. Organizations using affected Chrome versions face significant risk as the vulnerability can be leveraged for data theft, persistence mechanisms, or lateral movement within networks. The impact is particularly severe in enterprise environments where developers frequently use DevTools for debugging purposes, potentially creating numerous potential entry points for attackers.
Mitigation strategies for CVE-2021-30567 focus primarily on immediate software updates and operational security measures. The most effective immediate response is upgrading to Chrome version 92.0.4515.107 or later, which includes patches addressing the memory management issues within DevTools. Organizations should implement comprehensive patch management processes to ensure all affected systems are updated promptly, particularly in environments where developers regularly access DevTools. Network administrators should monitor for suspicious DevTools usage patterns and consider implementing additional security controls such as browser hardening configurations that restrict access to potentially dangerous features. Security teams should also conduct regular vulnerability assessments focusing on browser components and developer tools, as these areas often represent overlooked attack surfaces. The vulnerability serves as a reminder of the importance of secure coding practices and proper memory management in browser environments, with recommendations aligning with industry standards such as those provided by the Open Web Application Security Project. Additional protective measures include implementing application whitelisting policies, restricting user permissions when using DevTools, and maintaining detailed monitoring of browser activities that could indicate exploitation attempts.