CVE-2016-6728 in Android
Summary
by MITRE
An elevation of privilege vulnerability in the kernel ION subsystem 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 Critical due to the possibility of a local permanent device compromise, which may require reflashing the operating system to repair the device. Android ID: A-30400942.
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Analysis
by VulDB Data Team • 09/30/2022
The vulnerability described in CVE-2016-6728 represents a critical elevation of privilege flaw within the Android kernel's ION subsystem, which was discovered and addressed by Google in their security patches released on November 5, 2016. This vulnerability resides in the kernel-level memory management component responsible for handling buffer allocation and management across various Android subsystems, making it a prime target for attackers seeking to escalate their privileges from user-space applications to kernel-level execution. The ION subsystem serves as a critical interface for memory allocation between different hardware components and software layers, including graphics processing units, camera modules, and other specialized processors within mobile devices.
The technical implementation of this vulnerability stems from improper input validation and memory handling within the kernel's ION driver, specifically in how it processes memory buffer operations and manages memory mapping structures. Attackers can exploit this flaw by crafting malicious applications that manipulate the ION subsystem through specific ioctl calls, leading to memory corruption that allows arbitrary code execution in kernel space. This type of vulnerability falls under CWE-121, which describes stack-based buffer overflow conditions, and more specifically aligns with CWE-787, representing out-of-bounds write vulnerabilities that can occur when kernel subsystems fail to properly validate memory boundaries during buffer operations. The exploitation process typically involves leveraging the kernel's memory management functions to overwrite critical kernel structures or function pointers, effectively allowing attackers to execute arbitrary code with the highest privileges available within the system.
The operational impact of this vulnerability extends far beyond typical application-level exploits, as successful exploitation grants attackers complete control over the device's kernel execution environment. This level of access enables malicious actors to bypass all standard Android security mechanisms, including SELinux policies, application sandboxing, and other runtime protections that normally prevent unauthorized access to system resources. The vulnerability's critical severity classification stems from the fact that exploitation can result in permanent device compromise, where attackers can install rootkits, modify system binaries, disable security features, and potentially render devices inoperable without complete system reinstallation. According to the ATT&CK framework, this vulnerability maps to techniques such as T1068 (Local Privilege Escalation) and T1059 (Command and Scripting Interpreter), where attackers can leverage kernel-level access to establish persistent footholds and execute malicious payloads with complete system control.
Mitigation strategies for CVE-2016-6728 require immediate implementation of Google's security patches released in November 2016, which included kernel-level fixes to the ION subsystem's memory handling routines and enhanced input validation mechanisms. Organizations and device manufacturers should prioritize deployment of these patches across all affected Android versions, particularly targeting devices running Android versions prior to 6.0 Marshmallow where the vulnerability was most prevalent. Additional defensive measures include implementing kernel address space layout randomization (KASLR) and other exploit mitigation techniques, though these provide only partial protection since the vulnerability itself is a fundamental flaw in the kernel's memory management. System administrators should also monitor for suspicious application behavior and implement mobile device management policies that restrict installation of untrusted applications, as the vulnerability requires a malicious application to be installed on the device to be exploited. The remediation process may require complete device reinstallation in severe cases where exploitation has already occurred, making proactive patch management and security monitoring essential for maintaining device integrity and preventing permanent compromise.