CVE-2016-10239 in Android
Summary
by MITRE
In TrustZone access control policy may potentially be bypassed in all Android releases from CAF using the Linux kernel due to improper input validation an integer overflow vulnerability leading to a buffer overflow could potentially occur and a buffer over-read vulnerability could potentially occur.
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Analysis
by VulDB Data Team • 12/24/2020
The vulnerability identified as CVE-2016-10239 represents a critical security flaw within the Android operating system's TrustZone implementation, specifically affecting all Android releases utilizing Code Aurora Forum (CAF) based Linux kernels. This vulnerability stems from inadequate input validation mechanisms that permit malicious actors to potentially bypass established access control policies governing the secure execution environment. The flaw exists at the intersection of hardware security features and software kernel implementations, creating a pathway for unauthorized access to protected system resources and sensitive data processing capabilities.
The technical root cause of this vulnerability involves an integer overflow condition that occurs during input validation processes within the kernel's TrustZone management components. When processing certain input parameters, the system fails to properly validate the size and boundaries of data structures, leading to an integer overflow that subsequently triggers buffer overflow conditions. This overflow can overwrite adjacent memory locations within the kernel's memory space, potentially corrupting critical system data or executing arbitrary code. Additionally, the vulnerability exposes the system to buffer over-read conditions, where the kernel attempts to read data beyond the allocated buffer boundaries, potentially leaking sensitive information from memory regions that should remain protected.
The operational impact of CVE-2016-10239 extends far beyond simple privilege escalation, as it fundamentally compromises the security architecture designed to isolate sensitive operations from regular system processes. Attackers exploiting this vulnerability could potentially gain access to cryptographic keys, secure storage areas, and other confidential data processed within the TrustZone environment. The vulnerability's persistence across multiple Android versions and CAF-based implementations means that a significant portion of the mobile ecosystem remains exposed, particularly affecting devices manufactured by various OEMs that utilize CAF's kernel modifications. This creates a substantial attack surface that could enable sophisticated adversaries to establish persistent access to mobile devices, potentially leading to data exfiltration, device takeover, or further exploitation within corporate networks.
Mitigation strategies for this vulnerability require immediate implementation of kernel-level patches that address the integer overflow conditions and strengthen input validation mechanisms. System administrators should prioritize updating device firmware and kernel components to versions that include proper bounds checking and overflow protection measures. The vulnerability aligns with CWE-190, which specifically addresses integer overflow conditions, and demonstrates characteristics consistent with ATT&CK technique T1068, involving the exploitation of system vulnerabilities for privilege escalation. Organizations should implement network monitoring solutions to detect anomalous behavior patterns that might indicate exploitation attempts, while also conducting comprehensive security assessments to identify any potential compromise within their mobile device fleets. The fix typically involves implementing proper input sanitization, boundary checks, and ensuring that all integer operations within the TrustZone management code are protected against overflow conditions that could lead to memory corruption and unauthorized access.