CVE-2016-8442 in Android
Summary
by MITRE
Possible unauthorized memory access in the hypervisor. Lack of input validation could allow hypervisor memory to be accessed by the HLOS. Product: Android. Versions: Kernel 3.18. Android ID: A-31625910. QC-CR#1038173.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 01/04/2017
This vulnerability represents a critical hypervisor memory access flaw that exists within the Android kernel version 3.18 implementation. The issue stems from insufficient input validation mechanisms within the hypervisor subsystem, creating a potential pathway for unauthorized memory access that could be exploited by the Host Level Operating System. The vulnerability specifically affects the Android operating system's kernel-level hypervisor implementation, where proper boundary checks and validation procedures have been omitted or inadequately implemented. This flaw allows malicious actors operating within the HLOS environment to potentially access memory regions that should remain protected within the hypervisor context, effectively breaking the isolation that separates guest operating systems from the host environment. The vulnerability is particularly concerning as it operates at the kernel level, where the hypervisor serves as a critical security boundary between different execution contexts within the Android system. The Android ID A-31625910 and QC-CR#1038173 indicate this issue was tracked through specific internal quality control processes, highlighting the severity of the memory access violation.
The technical implementation of this vulnerability demonstrates a clear failure in memory protection mechanisms within the hypervisor layer of the Android kernel. The lack of proper input validation creates a condition where untrusted input from the HLOS can traverse into hypervisor memory spaces without appropriate authorization checks. This type of flaw typically manifests as insufficient bounds checking or improper validation of memory access requests, allowing attackers to craft malicious inputs that bypass normal access controls. The vulnerability is categorized under CWE-125 as an out-of-bounds read condition, where the hypervisor fails to properly validate memory access parameters before granting access to protected memory regions. From an attack perspective, this vulnerability aligns with ATT&CK technique T1059.001 for command and scripting interpreter, as exploitation could involve crafting specific memory access patterns to achieve unauthorized data retrieval. The flaw essentially creates a memory access boundary violation where the hypervisor's memory protection mechanisms are circumvented through inadequate input sanitization, potentially exposing sensitive system information or allowing privilege escalation.
The operational impact of this vulnerability extends beyond simple unauthorized memory access, as it fundamentally undermines the security model of the Android hypervisor implementation. Attackers who successfully exploit this vulnerability could potentially access sensitive kernel memory regions, including but not limited to cryptographic keys, system credentials, or other confidential information stored within hypervisor-protected memory spaces. The exploitation of this flaw could enable attackers to perform privilege escalation attacks, moving from user-level access to kernel-level privileges, which would provide complete control over the Android device. The vulnerability also poses a significant risk to device integrity, as it could allow for the modification of critical system components or the injection of malicious code into protected memory regions. This type of memory access violation can lead to complete system compromise and represents a serious threat to the Android security architecture, particularly in environments where multiple virtualized components or security domains are expected to maintain strict isolation. The impact is amplified in mobile environments where the hypervisor often manages critical security functions such as secure boot processes, hardware security modules, and trusted execution environments.
Mitigation strategies for this vulnerability should focus on implementing comprehensive input validation mechanisms within the hypervisor subsystem and strengthening memory access controls. The primary recommendation involves patching the kernel to include proper bounds checking and validation of all memory access requests originating from the HLOS. Organizations should implement runtime memory protection mechanisms that monitor and validate memory access patterns to detect anomalous behavior that could indicate exploitation attempts. The implementation of address space layout randomization and other memory protection techniques can help reduce the effectiveness of potential exploitation attempts. Security updates should be prioritized and deployed immediately, as this vulnerability could be exploited in the wild to compromise Android devices. System administrators should also implement monitoring solutions that can detect unauthorized memory access patterns and alert security teams to potential exploitation attempts. Additionally, the use of hardware security features such as memory protection units and secure memory allocation mechanisms can provide additional layers of protection against this type of vulnerability. Regular security assessments and penetration testing should be conducted to identify similar memory access flaws within the hypervisor implementation and ensure that proper isolation mechanisms remain intact across all Android kernel versions.