CVE-2016-8393 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-3.10. Android ID: A-31911920.
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Analysis
by VulDB Data Team • 07/20/2020
The vulnerability identified as CVE-2016-8393 represents a critical elevation of privilege flaw within the Synaptics touchscreen driver component of Android systems running kernel version 3.10. This vulnerability resides in the kernel-level driver responsible for handling touchscreen input functionality, creating a pathway for malicious applications to escalate their privileges and gain unauthorized access to system-level operations. The flaw specifically affects Android devices where the Synaptics touchscreen driver is implemented, making it a widespread concern across numerous Android-based platforms that rely on this particular driver implementation.
The technical nature of this vulnerability stems from improper input validation and insufficient access controls within the Synaptics driver code. When a malicious application attempts to interact with the touchscreen driver through improper ioctl (input/output control) commands or memory manipulation techniques, the driver fails to properly validate the incoming requests. This validation failure creates an opportunity for privilege escalation, allowing a local attacker to execute arbitrary code with kernel-level privileges. The vulnerability is classified as a kernel-level flaw that operates at the intersection of hardware abstraction layer and system security boundaries, making it particularly dangerous as it bypasses traditional user-space security mechanisms. The issue manifests when the driver processes certain input commands without proper authorization checks, potentially allowing an attacker who has already compromised a privileged process to leverage this weakness for full system compromise.
The operational impact of CVE-2016-8393 extends beyond simple privilege escalation, as it provides attackers with complete control over the device's kernel space operations. This capability enables malicious actors to modify system files, install persistent backdoors, access sensitive user data, and potentially compromise the entire device functionality. The vulnerability's high severity rating reflects the requirement for an initial compromise of a privileged process, which is often achievable through other attack vectors such as phishing, malicious app distribution, or exploitation of other vulnerabilities within the Android ecosystem. Once the initial compromise occurs, attackers can utilize this kernel-level privilege escalation to maintain persistent access, making the device vulnerable to ongoing surveillance and data exfiltration. The attack surface is particularly concerning given that touchscreen drivers are integral components of mobile devices, making exploitation relatively straightforward for attackers with basic knowledge of Android kernel internals.
Mitigation strategies for CVE-2016-8393 primarily focus on patch management and system hardening approaches. Device manufacturers should implement immediate security updates that address the Synaptics driver vulnerability through proper input validation and access control mechanisms. The fix typically involves strengthening the driver's ioctl command handling to ensure proper authentication and authorization checks before processing any privileged operations. Organizations should also consider implementing runtime protection mechanisms such as kernel address space layout randomization and stack canaries to make exploitation more difficult. Additionally, security monitoring solutions should be deployed to detect unusual kernel-level activities that may indicate exploitation attempts. From a compliance perspective, this vulnerability aligns with CWE-284 (Improper Access Control) and may be categorized under ATT&CK technique T1068 (Exploitation for Privilege Escalation) within the MITRE ATT&CK framework. Regular security assessments and vulnerability scanning should be conducted to identify and remediate similar kernel-level vulnerabilities across the Android ecosystem, particularly focusing on third-party driver implementations that may contain similar security flaws.