CVE-2016-8451 in Android
Summary
by MITRE
An elevation of privilege vulnerability in the Synaptics touchscreen 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-3.4. Android ID: A-32178033.
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Analysis
by VulDB Data Team • 10/27/2022
The CVE-2016-8451 vulnerability represents a critical elevation of privilege flaw within the Synaptics touchscreen driver component of Android systems running kernel version 3.4. This vulnerability exists in the kernel-level driver responsible for processing touchscreen input events, creating a pathway for malicious applications to escalate their privileges and execute code with kernel-level permissions. The issue is particularly concerning because it leverages the inherent trust placed in hardware driver components, which operate at the most privileged level of the operating system. The vulnerability requires an initial compromise of a privileged process as a prerequisite, making it a sophisticated attack vector that targets the fundamental security boundaries of the Android platform.
This technical flaw stems from improper input validation and memory handling within the Synaptics touchscreen driver implementation, specifically in how the driver processes certain ioctl commands or data structures sent from user-space applications. The vulnerability manifests when the driver fails to properly validate input parameters or memory pointers, potentially allowing an attacker to craft malicious input that triggers a buffer overflow or use-after-free condition. According to CWE classification, this vulnerability aligns with CWE-121, heap-based buffer overflow, and CWE-125, out-of-bounds read, as the driver's insufficient bounds checking creates opportunities for memory corruption that can be exploited to gain kernel execution privileges. The attack surface is particularly wide given that touchscreen input is continuously processed by the driver, making it a persistent target for exploitation attempts.
The operational impact of CVE-2016-8451 extends far beyond simple privilege escalation, as successful exploitation provides attackers with complete control over the device's kernel space operations. This enables malicious actors to bypass all Android security mechanisms, including application sandboxing, SELinux policies, and other runtime protections that normally prevent unauthorized system access. The vulnerability can be leveraged to install persistent backdoors, modify system files, extract sensitive user data, or even disable security features entirely. From an ATT&CK framework perspective, this vulnerability maps to multiple techniques including privilege escalation through kernel exploits, persistence mechanisms, and credential access, making it a particularly dangerous threat vector. The fact that exploitation requires only a compromised privileged process indicates that attackers may have already gained some foothold through other attack vectors such as malicious applications or supply chain compromises.
Mitigation strategies for CVE-2016-8451 must address both immediate remediation and long-term security hardening. The most effective immediate solution involves applying the vendor-provided security patches that correct the input validation flaws in the Synaptics driver implementation. Organizations should also implement comprehensive monitoring for unusual kernel-level activities and ensure that all privileged processes are properly secured against unauthorized access. Device manufacturers should consider implementing additional runtime protections such as kernel address space layout randomization and stack canaries to make exploitation more difficult. From a defensive standpoint, security teams should monitor for indicators of compromise related to kernel-level modifications and implement proper application vetting procedures to prevent malicious applications from gaining the initial privileged access required for exploitation. The vulnerability underscores the critical importance of maintaining up-to-date driver components and implementing layered security approaches that reduce the attack surface available to potential adversaries.