CVE-2019-9276 in Android
Summary
by MITRE
In the Android kernel in the synaptics_dsx_htc touchscreen driver there is a possible out of bounds write due to a use after free. This could lead to a 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-2019-9276 resides within the Android kernel's synaptics_dsx_htc touchscreen driver component, representing a critical security flaw that undermines the integrity of the device's operating system. This issue manifests as a use after free condition that occurs when memory allocated to the touchscreen driver is freed but subsequently accessed, creating an exploitable scenario for privilege escalation. The vulnerability specifically affects devices running Android versions prior to 2019, making it particularly concerning given the widespread deployment of affected Android variants across various mobile platforms.
The technical implementation of this flaw involves a memory management error within the touchscreen driver's handling of device resources. When the driver processes touchscreen input events, it fails to properly validate memory references after deallocation, allowing an attacker to manipulate the freed memory location and write data beyond the intended bounds. This out of bounds write condition creates opportunities for arbitrary code execution within the kernel context, as the attacker can overwrite critical kernel structures or function pointers. The vulnerability's classification under CWE-416 indicates a use after free condition, which is a well-documented pattern of memory safety issues that frequently leads to privilege escalation exploits. The attack vector requires system execution privileges to be effective, meaning that an attacker must already have access to the device to leverage this vulnerability, though the ultimate goal remains achieving elevated privileges.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it can enable attackers to gain full system control over affected devices. Once exploited, the vulnerability allows for persistent access to device resources, enabling potential data theft, surveillance capabilities, or further exploitation of other system components. The lack of user interaction requirements for exploitation makes this vulnerability particularly dangerous, as it can be triggered automatically without any user awareness or intervention. This characteristic aligns with ATT&CK technique T1068 which describes the use of local privilege escalation techniques, and the vulnerability's nature fits within the broader category of kernel-level exploits that can be leveraged for persistent access. The flaw's presence in the touchscreen driver also raises concerns about supply chain security, as it affects devices from multiple manufacturers who utilize the same touchscreen driver components, potentially creating a widespread attack surface.
Mitigation strategies for CVE-2019-9276 focus primarily on applying timely security patches provided by device manufacturers and Google, which typically involve updating the kernel components and implementing proper memory validation routines. System administrators should prioritize patch deployment across all affected devices, particularly those handling sensitive data or operating in high-risk environments. Additional protective measures include implementing kernel address space layout randomization, disabling unnecessary touchscreen functionality when not actively required, and monitoring for anomalous system behavior that might indicate exploitation attempts. The vulnerability's remediation also emphasizes the importance of proper memory management practices in kernel modules, as highlighted by industry standards such as the CERT Secure Coding Standards that specifically address use after free conditions in kernel-level programming. Organizations should also consider implementing device integrity monitoring solutions that can detect unauthorized modifications to kernel components and provide early warning of potential exploitation attempts.