CVE-2021-37962 in Chrome
Summary
by MITRE • 10/09/2021
Use after free in Performance Manager in Google Chrome prior to 94.0.4606.54 allowed a remote attacker who had compromised the renderer process to potentially exploit heap corruption via a crafted HTML page.
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Analysis
by VulDB Data Team • 10/09/2021
This vulnerability represents a use-after-free condition in Google Chrome's Performance Manager component that existed prior to version 94.0.4606.54 and falls under the Common Weakness Enumeration category CWE-416. The flaw occurs when a renderer process is compromised by a remote attacker who can manipulate memory operations through a specially crafted html page. When the Performance Manager handles certain performance-related objects, it fails to properly manage object lifecycles, leading to situations where freed memory blocks are still referenced or accessed by subsequent operations. This type of vulnerability is particularly dangerous because it can enable attackers who have already gained access to the renderer process to escalate their privileges and potentially execute arbitrary code on the target system.
The technical exploitation pathway involves leveraging the compromised renderer process to trigger specific memory management sequences that cause objects to be freed from memory while still being referenced elsewhere in the application's execution flow. When the Performance Manager component attempts to access these freed memory locations, it can result in heap corruption that allows attackers to manipulate memory contents or control program execution flow. The vulnerability specifically affects Chrome's handling of performance monitoring data structures and can be triggered through malicious web content that forces the browser to perform certain operations on freed objects.
The operational impact of this vulnerability extends beyond simple privilege escalation as it provides attackers with a mechanism to bypass security boundaries within the browser sandbox. Once an attacker successfully exploits this use-after-free condition, they can potentially execute code with the privileges of the compromised renderer process, which typically operates with limited system access but can still provide a foothold for further attacks. The vulnerability's remote nature means that attackers do not need physical access to the target system and can exploit it through web-based attacks, making it particularly concerning for users who browse the internet regularly.
Mitigation strategies for this vulnerability include immediate patching of Chrome installations to version 94.0.4606.54 or later, which contains the necessary memory management fixes for the Performance Manager component. Organizations should also implement network-level protections such as web application firewalls and content filtering systems that can detect and block malicious html content. Additionally, browser hardening measures including sandboxing configurations, strict content security policies, and regular security updates help reduce the attack surface. From an ATT&CK framework perspective, this vulnerability relates to techniques involving privilege escalation and code execution through memory corruption, specifically leveraging the T1068 privilege escalation tactic and T1059 command and scripting interpreter techniques that could follow such exploitation.
The underlying cause of this vulnerability demonstrates the complexity of modern browser security architectures where multiple components must maintain proper object lifecycle management across different execution contexts. The Performance Manager's failure to properly handle reference counting or garbage collection in this scenario illustrates how seemingly isolated component flaws can create significant security risks when combined with existing compromise conditions. This vulnerability underscores the importance of comprehensive memory safety testing and the application of defensive programming practices throughout browser codebases, particularly in components that handle dynamic data structures and performance monitoring operations that are frequently accessed during web page rendering.