CVE-2016-3865 in Android
Summary
by MITRE
The Synaptics touchscreen driver in Android before 2016-09-05 on Nexus 5X and 9 devices allows attackers to gain privileges via a crafted application, aka internal bug 28799389.
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Analysis
by VulDB Data Team • 09/15/2022
The vulnerability identified as CVE-2016-3865 represents a critical privilege escalation flaw within the Synaptics touchscreen driver component of Android operating systems. This issue specifically affected Nexus 5X and Nexus 9 devices running Android versions prior to the security patch released on September 5, 2016. The vulnerability stems from improper input validation and privilege handling within the touchscreen driver subsystem that processes touch events and related hardware interactions. Attackers could exploit this weakness by installing a malicious application that leverages the driver's insufficient access controls to elevate their privileges from standard user level to system level execution. The flaw operates at the kernel level where touchscreen input processing occurs, making it particularly dangerous as it bypasses normal Android security boundaries and access controls that typically protect system resources from unauthorized modification. This type of vulnerability falls under CWE-264, which addresses permissions, privileges, and access controls, specifically targeting improper privilege management in kernel modules.
The technical exploitation of this vulnerability requires an attacker to craft a malicious application that can interact with the Synaptics touchscreen driver interface in a manner that triggers the privilege escalation mechanism. The attack vector involves sending specially crafted touch events or driver commands that exploit a buffer overflow or improper validation in the driver's input processing functions. Once successfully exploited, the malicious application gains full system privileges, enabling it to modify system files, access sensitive data, install additional malware, or completely compromise the device's security posture. The vulnerability's impact extends beyond simple privilege escalation as it provides attackers with the ability to bypass Android's security model and potentially access all device resources, including encrypted storage, user credentials, and communication channels. This flaw represents a significant weakness in the Android security architecture as it demonstrates how hardware driver components can serve as attack vectors for system-level compromise, aligning with ATT&CK technique T1068 which covers local privilege escalation through kernel exploits.
The operational implications of CVE-2016-3865 are severe for affected Nexus 5X and Nexus 9 users, as it transforms any installed application into a potential system compromise tool. Devices running vulnerable Android versions become susceptible to attacks that can result in complete device takeover, data exfiltration, and persistent backdoor installation. The vulnerability affects a wide range of applications and services that rely on touchscreen input, making it particularly dangerous as legitimate applications may inadvertently trigger the exploit conditions. Organizations and individuals using these devices face significant risk of unauthorized access to sensitive information, including personal data, corporate credentials, and communication records. The vulnerability's persistence across multiple device models and Android versions indicates a systemic issue in how touchscreen driver components were implemented and tested for security. Security researchers have noted that this type of kernel-level privilege escalation vulnerability can be particularly challenging to detect and remediate, as it requires comprehensive system-level analysis and often necessitates full device reinstallation to ensure complete mitigation. The flaw underscores the importance of proper input validation and access control implementation in kernel modules, as well as the need for comprehensive security testing of hardware driver components within mobile operating systems.
Mitigation strategies for CVE-2016-3865 primarily involve applying the security patch released by Google on September 5, 2016, which addressed the privilege escalation vulnerability in the Synaptics touchscreen driver. Users should ensure their devices receive all available security updates from Google, particularly for the Nexus 5X and Nexus 9 models that were specifically affected by this vulnerability. Device administrators should implement strict application vetting processes to prevent installation of untrusted applications that could potentially exploit this vulnerability. Network security teams should monitor for indicators of compromise related to this vulnerability, including unusual system behavior or unauthorized access attempts. The vulnerability's classification as a kernel-level privilege escalation issue means that traditional mobile security solutions may not provide adequate protection, requiring more comprehensive system-level security measures. Organizations should consider implementing device management policies that enforce automatic security updates and maintain inventory tracking of affected devices. Regular security assessments of mobile device environments should include verification of driver component security status and monitoring for similar privilege escalation vulnerabilities in other hardware drivers. The incident highlights the necessity of continuous security monitoring and rapid response capabilities for mobile platforms, as well as the importance of maintaining up-to-date threat intelligence related to kernel-level exploits in mobile operating systems.