CVE-2016-1655 in Chrome
Summary
by MITRE
Google Chrome before 50.0.2661.75 does not properly consider that frame removal may occur during callback execution, which allows remote attackers to cause a denial of service (use-after-free) or possibly have unspecified other impact via a crafted extension.
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Analysis
by VulDB Data Team • 07/25/2022
The vulnerability identified as CVE-2016-1655 represents a critical use-after-free condition within Google Chrome versions prior to 50.0.2661.75. This flaw specifically manifests in the browser's handling of frame removal during callback execution processes, creating a scenario where malicious actors can exploit the timing gap between frame destruction and callback completion. The issue stems from Chrome's extension architecture where frame objects may be destroyed while callbacks are still executing, leading to memory access violations that can result in system instability or potential code execution. This vulnerability is particularly dangerous because it operates within the browser's extension framework, which typically runs with elevated privileges and has extensive access to user data and system resources.
The technical implementation of this vulnerability involves the improper synchronization between frame lifecycle management and callback execution contexts. When an extension triggers a callback function that references frame objects, and simultaneously removes or destroys those frames during the callback execution, Chrome's memory management system fails to properly track the reference counts or invalidate the pointers. This creates a window of opportunity where the callback attempts to access memory that has already been freed or reallocated, resulting in undefined behavior. The flaw aligns with CWE-416, which describes use-after-free vulnerabilities where a pointer is used after the memory it points to has been freed, and may also relate to CWE-129, which addresses improper validation of array indices and buffer bounds. The vulnerability can be exploited through malicious browser extensions that manipulate frame objects in a way that triggers the race condition during callback processing.
From an operational perspective, this vulnerability presents significant risks to end users and system administrators. Attackers can craft malicious extensions that, when installed or activated, trigger the use-after-free condition to cause denial of service attacks that crash the browser or render system components unusable. More concerning is the potential for unspecified other impacts that could include privilege escalation or remote code execution depending on the specific memory corruption patterns. The attack vector is particularly insidious because it requires only the installation of a malicious extension, which can be distributed through various channels including official extension stores. This vulnerability affects the core browser security model by allowing extensions to potentially bypass memory safety mechanisms, undermining the sandboxing principles that protect users from malicious code. The impact extends beyond individual users to enterprise environments where browser security is critical for protecting sensitive data and maintaining system integrity.
Mitigation strategies for CVE-2016-1655 focus primarily on immediate patching and browser updates to ensure users are running Chrome version 50.0.2661.75 or later. System administrators should implement strict extension vetting processes and avoid installing third-party extensions from untrusted sources. The vulnerability demonstrates the importance of proper memory management in browser engines and highlights the need for robust callback execution frameworks that properly handle object lifecycle events. Organizations should also consider implementing browser hardening measures such as disabling unnecessary extension capabilities and using automated patch management systems. From a threat modeling perspective, this vulnerability aligns with ATT&CK technique T1176 which covers browser extensions as a means of persistence and privilege escalation. The incident underscores the critical importance of maintaining up-to-date browser software and implementing comprehensive security monitoring to detect and respond to exploitation attempts. Regular security assessments of browser extension ecosystems and user behavior monitoring can help identify potential exploitation attempts before they result in successful attacks.