CVE-2016-6742 in Android
Summary
by MITRE
An elevation of privilege vulnerability in the Synaptics touchscreen driver in Android before 2016-11-05 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. Android ID: A-30799828.
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Analysis
by VulDB Data Team • 09/30/2022
The vulnerability identified as CVE-2016-6742 represents a critical elevation of privilege flaw within the Synaptics touchscreen driver component of Android operating systems. This vulnerability specifically affects Android versions prior to the 2016-11-05 security patch release, creating a significant security risk for affected devices. The flaw allows a locally running malicious application to escalate its privileges and execute arbitrary code with kernel-level permissions, fundamentally compromising the system's security model. The vulnerability is classified as High severity due to the requirement of first compromising a privileged process, which creates a complex attack vector that requires additional initial compromise steps before the kernel-level execution can occur.
The technical implementation of this vulnerability stems from improper input validation and memory handling within the Synaptics touchscreen driver kernel module. When a malicious application attempts to interact with the touchscreen driver through improper ioctl commands or malformed data structures, the driver fails to properly validate the input parameters before processing them. This lack of proper bounds checking and parameter validation creates a buffer overflow or similar memory corruption condition that can be exploited to gain unauthorized code execution within the kernel context. The flaw exists in the driver's handling of touchscreen input events and communication protocols, where insufficient sanitization allows attacker-controlled data to overwrite critical kernel memory structures.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it fundamentally undermines the Android security model's principle of least privilege and kernel isolation. Once exploited, the malicious application can gain complete control over the device's kernel, enabling it to modify system files, disable security features, install persistent backdoors, or extract sensitive user data. The vulnerability's exploitation requires an initial compromise of a privileged process, which aligns with ATT&CK technique T1068 for privilege escalation, but the subsequent kernel-level execution creates a persistent threat that can bypass most traditional security controls. This makes the vulnerability particularly dangerous in environments where devices may be compromised through other attack vectors, as it provides a reliable path for maintaining persistence and escalating privileges.
Mitigation strategies for CVE-2016-6742 focus primarily on applying the Android security patches released on or after 2016-11-05, which address the specific input validation issues within the Synaptics driver. Organizations and users should prioritize immediate patch deployment to prevent exploitation, as the vulnerability's impact is severe enough to warrant urgent remediation. Additional defensive measures include implementing application whitelisting to prevent unauthorized applications from running, monitoring for suspicious kernel-level activity, and maintaining up-to-date endpoint protection solutions that can detect anomalous behavior patterns associated with privilege escalation attempts. The vulnerability also highlights the importance of proper driver security testing and input validation practices, aligning with CWE categories related to improper input validation and buffer overflows. Security teams should conduct regular vulnerability assessments to identify similar issues in other device drivers and kernel components, as this type of vulnerability demonstrates the critical need for robust kernel security practices in mobile operating systems.