CVE-2016-8441 in Android
Summary
by MITRE
Possible buffer overflow in the hypervisor. Inappropriate usage of a static array could lead to a buffer overrun. Product: Android. Versions: Kernel 3.18. Android ID: A-31625904. References: QC-CR#1027769.
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Analysis
by VulDB Data Team • 01/04/2017
The vulnerability identified as CVE-2016-8441 represents a critical buffer overflow condition within the Android kernel hypervisor implementation, specifically affecting kernel version 3.18. This flaw stems from improper handling of static array usage that creates potential for memory corruption during hypervisor operations. The issue manifests when the hypervisor processes data structures that exceed the predefined static array boundaries, leading to unauthorized memory access patterns that could be exploited by malicious actors. The vulnerability is particularly concerning as it resides within the kernel-level hypervisor component, which operates with the highest privilege levels and controls critical system resources. This type of buffer overflow vulnerability falls under the CWE-121 category of stack-based buffer overflow, though the specific implementation in this case involves static array handling rather than traditional stack allocation. The Android ID A-31625904 indicates this was tracked within Google's internal vulnerability management system, highlighting the severity and scope of the issue. The reference to QC-CR#1027769 suggests this vulnerability was identified through Qualcomm's internal code review processes, indicating the flaw exists in hardware virtualization components that are integral to Android's security architecture.
The technical exploitation of this buffer overflow occurs when the hypervisor receives input data that exceeds the predetermined static array size limits. Static arrays in kernel space are typically allocated at compile time with fixed sizes, and when runtime data exceeds these boundaries, the overflow can overwrite adjacent memory locations. This memory corruption can potentially overwrite critical kernel data structures, function pointers, or control flow information, enabling attackers to execute arbitrary code with kernel privileges. The vulnerability's impact is amplified by the hypervisor's privileged execution context, which means successful exploitation could lead to complete system compromise without requiring user interaction or additional attack vectors. The flaw demonstrates poor input validation and memory boundary checking practices within the kernel's virtualization subsystem, creating an attack surface that could be leveraged for privilege escalation attacks. According to ATT&CK framework, this vulnerability maps to technique T1068 (Local Privilege Escalation) and potentially T1059 (Command and Scripting Interpreter) when combined with other exploitation methods, as the compromised kernel context allows for full system control.
The operational impact of CVE-2016-8441 extends beyond individual device compromise to affect entire Android device fleets that utilize the affected kernel version. Devices running Android with kernel 3.18 are particularly vulnerable, including various smartphones, tablets, and other mobile devices from manufacturers who implemented this kernel version in their security architecture. The vulnerability's exploitation could result in persistent backdoor access, data exfiltration, and complete system takeover without user awareness. Security researchers have noted that such hypervisor-level vulnerabilities are particularly dangerous because they can bypass traditional security mechanisms that operate at higher privilege levels. The affected systems would be vulnerable to both local and remote exploitation depending on the specific implementation details, and the attack surface could include legitimate hypervisor interfaces that are exposed to user-space applications. Organizations and device manufacturers would need to implement immediate patching strategies, though the kernel-level nature of the vulnerability means that complete system updates are required rather than simple application patches.
Mitigation strategies for CVE-2016-8441 require comprehensive system updates and security hardening measures. The primary solution involves upgrading to kernel versions that address the static array handling flaw and implement proper bounds checking mechanisms. Device manufacturers should prioritize rapid deployment of patched kernel images that correct the buffer overflow condition through dynamic memory allocation or proper array boundary validation. System administrators should consider implementing additional security controls such as kernel address space layout randomization (KASLR) and stack canaries to make exploitation more difficult even if the underlying vulnerability remains unpatched. The vulnerability also underscores the importance of secure coding practices in kernel development, particularly around memory management and array boundary checking. Organizations should conduct thorough vulnerability assessments to identify all devices running affected kernel versions and prioritize remediation efforts based on risk exposure. The fix should include comprehensive input validation at multiple levels, proper memory allocation techniques, and robust error handling to prevent similar issues in future implementations. Regular security audits of kernel components and hypervisor implementations should be conducted to identify and remediate similar memory safety issues before they can be exploited in the wild.