CVE-2019-9458 in Android
Summary
by MITRE
In the Android kernel in the video driver there is a use after free due to a race condition. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.
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Analysis
by VulDB Data Team • 08/13/2020
The vulnerability identified as CVE-2019-9458 represents a critical use after free condition within the Android kernel's video driver component, demonstrating a fundamental race condition flaw that enables local privilege escalation. This vulnerability exists at the kernel level where the video driver fails to properly synchronize access to memory resources during concurrent operations, creating an exploitable window where freed memory can be accessed and manipulated by malicious code. The flaw specifically manifests when the kernel processes video driver operations that involve memory allocation and deallocation sequences, where timing dependencies between concurrent threads or processes can result in a scenario where a memory region is freed while still being referenced by another execution path. The race condition occurs during the handling of video buffer management operations where the kernel's video driver implementation does not adequately protect against simultaneous access patterns that could lead to memory corruption.
The technical impact of this vulnerability extends beyond simple memory corruption to provide a pathway for local privilege escalation, allowing an attacker with minimal privileges to gain elevated system access without requiring additional execution capabilities or user interaction. The exploitation mechanism relies on the attacker's ability to control the timing of concurrent operations within the video driver subsystem, specifically targeting the memory management operations that occur during video processing tasks. This vulnerability is particularly concerning because it operates entirely within the kernel space, meaning that successful exploitation can result in complete system compromise and elevation to root privileges. The lack of user interaction requirement makes this vulnerability especially dangerous as it can be exploited automatically without any user involvement, potentially enabling automated attacks that could be deployed in various threat scenarios.
From a security perspective, this vulnerability aligns with CWE-416, which describes the use after free condition, and demonstrates how race conditions in kernel-level code can create persistent security weaknesses. The attack pattern follows the ATT&CK framework's privilege escalation techniques, specifically targeting kernel-level vulnerabilities to achieve system-level control. The operational impact includes potential complete system compromise, data exfiltration capabilities, and the ability to maintain persistent access through elevated privileges. Organizations should consider this vulnerability as part of their broader security posture assessment, particularly in environments where Android devices are used for sensitive operations. The vulnerability's exploitation requires sophisticated understanding of kernel memory management and concurrent programming patterns, making it a sophisticated target for advanced persistent threats.
Mitigation strategies for CVE-2019-9458 should focus on immediate patch application from Android security updates, which typically address the race condition by implementing proper synchronization mechanisms within the video driver code. System administrators should also consider implementing additional security controls such as kernel address space layout randomization, memory protection mechanisms, and monitoring for anomalous video driver behavior. The vulnerability highlights the importance of thorough testing for race conditions in kernel code and the need for proper synchronization primitives to prevent concurrent access violations. Regular security assessments of kernel components and video driver implementations should be conducted to identify similar race condition vulnerabilities that could provide similar privilege escalation pathways. Organizations should also implement monitoring solutions that can detect unusual patterns in video processing operations that might indicate exploitation attempts.