CVE-2023-20835 in MT6895
Summary
by MITRE • 09/04/2023
In camsys, there is a possible use after free due to a race condition. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation. Patch ID: ALPS07341261; Issue ID: ALPS07326570.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 10/22/2024
The vulnerability identified as CVE-2023-20835 represents a critical use-after-free condition within the camsys component of an Android-based system. This flaw arises from a race condition that occurs during the handling of memory operations, creating a window where freed memory regions can be accessed and potentially reused by malicious processes. The vulnerability specifically affects systems where the camsys module manages camera-related functionalities and memory allocation for multimedia processing tasks. The race condition manifests when multiple threads or processes attempt to access the same memory resource simultaneously, leading to inconsistent state management and potential memory corruption scenarios.
The technical implementation of this vulnerability stems from improper synchronization mechanisms within the camsys subsystem, which fails to adequately protect shared resources during concurrent access scenarios. When the system processes camera data streams or manages multimedia buffers, the memory management functions do not properly enforce mutual exclusion or atomic operations. This creates a scenario where one thread frees a memory block while another thread simultaneously attempts to access or modify that same memory location, resulting in undefined behavior. The flaw operates at the kernel level or system-level service context where privilege escalation opportunities exist, particularly when the compromised memory region contains critical system structures or function pointers.
The operational impact of this vulnerability extends significantly beyond simple memory corruption, as it enables local privilege escalation to system-level execution privileges without requiring any user interaction. This means that any local process or malicious application running with standard user privileges can potentially exploit this condition to gain elevated system access. The implications are severe from a security standpoint since the attacker does not need to trick users into performing specific actions, making the attack surface much broader. The vulnerability essentially allows for complete system compromise from a local perspective, enabling access to sensitive data, modification of system configurations, and potential persistence mechanisms within the affected platform.
Mitigation strategies for CVE-2023-20835 must focus on addressing the underlying race condition through proper synchronization mechanisms and memory management protocols. System administrators should immediately apply the provided patch ALPS07341261 which contains the necessary code modifications to resolve the race condition in the camsys component. The patch likely implements proper mutex locking, atomic operations, or other concurrency control mechanisms to prevent simultaneous access to shared memory resources. Additionally, security teams should consider implementing runtime monitoring for suspicious memory access patterns and potentially disable unnecessary camera services when not actively in use. From a defensive perspective, this vulnerability aligns with CWE-416, which addresses use-after-free conditions, and represents a significant concern within the ATT&CK framework under privilege escalation techniques. Organizations should also implement comprehensive patch management processes to ensure timely deployment of security updates and consider conducting vulnerability assessments to identify similar race conditions in other system components. The vulnerability demonstrates the critical importance of proper concurrency control in system-level software development and highlights the potential for seemingly isolated memory management issues to result in severe privilege escalation capabilities.