CVE-2016-6785 in Android
Summary
by MITRE
An elevation of privilege vulnerability in the MediaTek driver could enable a local malicious application to execute arbitrary code within the context of the kernel. This issue is rated as High because it first requires compromising a privileged process. Product: Android. Versions: Kernel-3.10. Android ID: A-31748056. References: MT-ALPS02961400.
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Analysis
by VulDB Data Team • 07/20/2020
The vulnerability identified as CVE-2016-6785 represents a critical elevation of privilege flaw within MediaTek driver components that operates at the kernel level of Android systems. This issue stems from improper access control mechanisms within the driver implementation, allowing a local malicious application to escalate its privileges and execute arbitrary code with kernel-level permissions. The vulnerability specifically affects Android devices running kernel version 3.10 and is classified as High severity due to the privileged process compromise requirement, though this still represents a significant security risk. The MediaTek driver in question handles hardware-specific functionalities and maintains direct access to system resources, making it a prime target for attackers seeking kernel-level access. This flaw directly violates the principle of least privilege and demonstrates inadequate input validation and access control checks within the driver's code structure.
The technical exploitation of this vulnerability occurs through a privilege escalation vector that allows a malicious application to manipulate the MediaTek driver's behavior and gain unauthorized kernel access. The flaw likely involves improper validation of user-space inputs passed to kernel-space driver functions, enabling a malicious application to craft specific inputs that trigger unexpected behavior within the driver. This allows the attacker to execute code with elevated privileges, effectively bypassing Android's security model and gaining full control over the kernel execution environment. The vulnerability operates at the kernel level, meaning that once exploited, it provides attackers with complete system control including the ability to read/write any memory location, modify system files, and potentially install persistent backdoors. This type of vulnerability aligns with CWE-284 Access Control Issues, specifically targeting improper access control mechanisms in kernel drivers.
The operational impact of CVE-2016-6785 extends beyond simple privilege escalation to encompass complete system compromise and data exfiltration capabilities. A successful exploitation could enable attackers to bypass all Android security mechanisms including SELinux policies, application sandboxing, and other runtime protections. The vulnerability affects devices with MediaTek chipsets running Android 6.0 and earlier versions, making it particularly dangerous given the widespread adoption of MediaTek processors in mobile devices. Attackers could leverage this vulnerability to install rootkits, steal sensitive user data, monitor communications, and maintain persistent access to compromised devices. The requirement for an initial compromise of a privileged process means that attackers would need to first gain access to a legitimate application or service, but once achieved, the kernel-level access provides unlimited system control. This vulnerability falls under ATT&CK technique T1068 Privilege Escalation and T1059 Command and Scripting Interpreter, demonstrating how kernel-level access enables complete system compromise.
Mitigation strategies for CVE-2016-6785 primarily focus on system updates and patch management, as MediaTek and Google released security patches to address this specific vulnerability. Device manufacturers should ensure timely deployment of security updates that include kernel patches and driver updates from MediaTek. System administrators should implement strict application control policies to limit the execution of potentially malicious applications and monitor for unusual system behavior that might indicate exploitation attempts. Additionally, organizations should consider implementing mobile device management solutions that can enforce security policies and detect anomalous kernel-level activities. Regular security assessments of kernel modules and driver components should be conducted to identify similar access control issues. The vulnerability highlights the importance of secure coding practices in kernel drivers and proper input validation mechanisms, emphasizing the need for comprehensive security testing of low-level system components. Device users should maintain regular update schedules and avoid sideloading applications from untrusted sources that could potentially exploit such vulnerabilities.