CVE-2016-6745 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-31252388.
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Analysis
by VulDB Data Team • 09/30/2022
The vulnerability identified as CVE-2016-6745 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 local malicious applications to execute arbitrary code with elevated privileges. The vulnerability's classification as High severity stems from its requirement to first compromise a privileged process, which creates a dangerous attack vector that could potentially enable full system compromise. The Android ID A-31252388 further emphasizes the significance of this flaw within the Android security ecosystem. The Synaptics touchscreen driver serves as a critical system component that interfaces directly with hardware input mechanisms, making it an attractive target for attackers seeking to gain deeper system access.
The technical exploitation of this vulnerability occurs through improper input validation and memory handling within the Synaptics driver implementation. When a malicious application attempts to interact with the touchscreen driver through kernel-level interfaces, the driver fails to properly validate the input data or enforce appropriate access controls. This creates a condition where unprivileged code can manipulate kernel memory structures or execute arbitrary code within kernel context, effectively bypassing the fundamental security boundaries that separate user-space applications from the privileged kernel environment. The flaw likely involves buffer overflow conditions, use-after-free vulnerabilities, or improper privilege checks that allow malicious input to trigger unintended kernel execution paths. According to CWE classification standards, this vulnerability would fall under CWE-20, "Improper Input Validation," and potentially CWE-119, "Improper Access Control," given the memory corruption aspects of the flaw.
The operational impact of CVE-2016-6745 extends beyond simple privilege escalation to potentially enable complete system compromise and persistent access. Once an attacker successfully exploits this vulnerability, they can execute code with kernel-level privileges, which provides access to all system resources, memory spaces, and hardware components. This level of access allows for complete system takeover, data exfiltration, persistent backdoor installation, and the ability to modify or disable critical security features. The vulnerability's exploitation requires the attacker to first compromise a privileged process, which may involve social engineering or exploiting other vulnerabilities to gain initial access. However, once the initial compromise occurs, the kernel-level execution capability provides a powerful attack surface that can be leveraged for further exploitation, persistence, and lateral movement within the system. This vulnerability directly aligns with ATT&CK techniques involving privilege escalation and persistence mechanisms.
Mitigation strategies for CVE-2016-6745 primarily focus on applying the Android security patches released in November 2016, which address the specific kernel-level flaws in the Synaptics driver implementation. System administrators and device manufacturers should prioritize immediate deployment of the security updates to prevent exploitation. Additionally, implementing runtime protections such as kernel address space layout randomization kASLR, stack canaries, and control flow integrity checks can provide defense-in-depth measures against similar vulnerabilities. Device manufacturers should also consider implementing secure coding practices and thorough security testing for third-party drivers, particularly those that interface with hardware components like touchscreens that have direct kernel access. Regular security audits of driver components and maintaining updated security patches for all system components remain essential practices for preventing exploitation of similar kernel-level vulnerabilities. Organizations should also implement monitoring solutions that can detect anomalous kernel-level activity that may indicate exploitation attempts, as the vulnerability's nature makes it particularly challenging to detect through conventional security measures.