CVE-2019-9273 in Android
Summary
by MITRE
In the Android kernel in the synaptics_dsx_htc touchscreen driver there is a possible use after free due to improper locking. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation.
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Analysis
by VulDB Data Team • 12/13/2023
The vulnerability identified as CVE-2019-9273 resides within the Android kernel's synaptics_dsx_htc touchscreen driver, representing a critical security flaw that could enable local privilege escalation. This issue stems from improper locking mechanisms within the driver's implementation, creating a use-after-free condition that adversaries can exploit to gain elevated system privileges. The vulnerability specifically affects devices running Android versions prior to 2019, making it particularly concerning given the widespread deployment of affected touchscreen hardware across various mobile platforms.
The technical root cause of this vulnerability lies in the driver's inadequate synchronization mechanisms when handling memory allocations and deallocations. When multiple threads or processes attempt to access the same touchscreen driver resources simultaneously, the lack of proper locking protocols creates a race condition scenario. This race condition allows an attacker to manipulate the driver's memory management functions in such a way that freed memory blocks are accessed after being deallocated, resulting in a use-after-free condition. The CWE-416 identifier applies here as the vulnerability involves the use of memory after it has been freed, while CWE-362 specifically addresses the race condition that enables this exploitation path.
The operational impact of CVE-2019-9273 extends beyond simple privilege escalation, as it provides attackers with system-level execution privileges that could be leveraged to compromise the entire device. Since no user interaction is required for exploitation, this vulnerability can be triggered automatically when the touchscreen driver is accessed or when the device enters specific operational states. The attack surface is broad as the touchscreen driver is continuously active during normal device operation, making persistent exploitation possible. This vulnerability aligns with ATT&CK technique T1068 which covers local privilege escalation through kernel exploits, and T1059 which encompasses command execution within system processes.
Mitigation strategies for CVE-2019-9273 primarily focus on immediate system updates and patches provided by device manufacturers and Google. The most effective remediation involves applying the latest Android security patches that include proper locking mechanisms within the synaptics_dsx_htc driver implementation. Organizations should prioritize updating all affected devices to versions that contain the patched driver code, which typically includes enhanced mutex locking protocols and proper memory management synchronization. Additionally, system administrators should implement monitoring solutions that can detect anomalous driver behavior or memory access patterns that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of proper kernel driver security practices and highlights how seemingly benign hardware drivers can become significant attack vectors when inadequate locking mechanisms are implemented.