CVE-2016-6743 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-30937462.
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Analysis
by VulDB Data Team • 09/30/2022
The vulnerability identified as CVE-2016-6743 represents a critical elevation of privilege flaw within the Synaptics touchscreen driver component of Android operating systems. This weakness existed in Android versions prior to the 2016-11-05 security patch release and fundamentally compromised the kernel's integrity by allowing a local malicious application to execute arbitrary code with elevated privileges. The vulnerability operates at the kernel level, which means that successful exploitation would grant the attacker complete control over the device's core operating system functions. The issue is classified as High severity because it requires initial compromise of a privileged process as a prerequisite, but once achieved, the attacker gains the ability to perform actions that should normally be restricted to system-level components. This represents a significant breach in Android's security model where the boundary between user-space applications and kernel-space operations becomes compromised.
The technical implementation of this vulnerability stems from improper input validation and memory handling within the Synaptics touchscreen driver module. The flaw occurs when the driver processes certain malformed input data from touchscreen events, allowing an attacker to manipulate memory structures and execute code with kernel-level privileges. This type of vulnerability typically falls under CWE-119, which addresses weaknesses in memory handling, and specifically relates to improper handling of memory access violations or buffer overflows that could be exploited to gain unauthorized access to privileged execution contexts. The exploitation process involves crafting malicious touchscreen input sequences that trigger the vulnerable code path within the driver, effectively bypassing Android's normal security boundaries between applications and the underlying kernel. Attackers would need to first gain execution privileges within a legitimate application context, then leverage this vulnerability to escalate their privileges to kernel level, where they could perform actions such as modifying system files, installing persistent backdoors, or extracting sensitive data from protected memory regions.
The operational impact of CVE-2016-6743 extends beyond simple privilege escalation, as it provides attackers with complete control over affected Android devices. Once exploited, the malicious application could modify system binaries, create new user accounts with administrative privileges, monitor all user input including passwords and sensitive communications, and potentially install additional malware that persists across device reboots. The vulnerability affects all Android devices that utilize Synaptics touchscreen controllers and were running versions prior to the 2016-11-05 patch, making it particularly dangerous as it could affect a wide range of smartphones, tablets, and other mobile devices. This vulnerability also aligns with ATT&CK technique T1068, which involves the use of local privilege escalation techniques, and demonstrates how attackers can leverage driver-level vulnerabilities to achieve system compromise. The impact is particularly severe in enterprise environments where mobile devices may contain sensitive corporate data, and in scenarios where devices are used in critical infrastructure applications where unauthorized access could lead to significant operational disruptions.
Mitigation strategies for CVE-2016-6743 primarily involve applying the official Android security patches released on 2016-11-05, which address the specific memory handling issues within the Synaptics driver. System administrators should ensure that all Android devices within their organization are updated to the latest security patches and that automatic update mechanisms are enabled where possible. Additionally, organizations should implement mobile device management solutions that can enforce security policies and monitor for unauthorized applications that might attempt to exploit this vulnerability. Network-level monitoring should be enhanced to detect suspicious activities that could indicate exploitation attempts, particularly around kernel-level memory access patterns and unusual privilege escalation events. Device hardening measures including disabling unnecessary touchscreen functionality and restricting application permissions can further reduce the attack surface. Security teams should also consider implementing behavioral monitoring solutions that can detect anomalous kernel-level activities that might indicate exploitation of this vulnerability, as well as conducting regular vulnerability assessments to identify any remaining unpatched devices within their network infrastructure. The vulnerability serves as a reminder of the critical importance of maintaining up-to-date device firmware and the potential risks associated with driver-level vulnerabilities in mobile operating systems.