CVE-2015-9031 in Android
Summary
by MITRE
In all Android releases from CAF using the Linux kernel, a TZ memory address is exposed to HLOS by HDCP.
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Analysis
by VulDB Data Team • 12/27/2020
The vulnerability identified as CVE-2015-9031 represents a critical security flaw in Android devices that utilize Qualcomm's Android Framework (CAF) and the underlying Linux kernel architecture. This issue specifically affects the TrustZone (TZ) memory management system where sensitive memory addresses are inadvertently exposed to the Host Linux Operating System (HLOS) through the High-bandwidth Digital Content Protection (HDCP) protocol implementation. The exposure occurs during the normal operation of HDCP functionality which is designed to protect digital audio and video content from unauthorized copying during transmission between devices.
The technical flaw stems from improper memory management within the Qualcomm kernel modules that handle HDCP operations. When HDCP is active, the system exposes memory addresses that should remain within the secure TrustZone environment to the less-privileged HLOS context. This memory address leakage creates a potential attack surface where malicious actors could exploit the exposed addresses to gain unauthorized access to sensitive kernel memory regions. The vulnerability is particularly concerning because TrustZone is specifically designed to isolate secure processing environments from the main operating system, and this exposure undermines that fundamental security boundary. The flaw exists across multiple Android versions and kernel implementations, making it a widespread issue affecting numerous device models from various manufacturers.
The operational impact of CVE-2015-9031 extends beyond simple information disclosure, as it provides attackers with potential pathways for privilege escalation and system compromise. An attacker who can leverage the exposed memory addresses could potentially manipulate kernel memory structures, bypass security controls, or execute arbitrary code within the kernel space. This vulnerability aligns with CWE-200 (Information Exposure) and potentially CWE-264 (Permissions, Privileges, and Access Controls) as it exposes sensitive memory locations that should remain protected. The threat model for this vulnerability includes advanced persistent threats that could use the exposed addresses to conduct sophisticated attacks against mobile devices, potentially compromising user data and device integrity. The impact is particularly severe in enterprise environments where mobile devices may contain sensitive corporate information and where the compromise of a single device could lead to broader network infiltration.
Mitigation strategies for CVE-2015-9031 focus on both immediate patching and architectural improvements to prevent similar issues in the future. Device manufacturers should prioritize applying the relevant kernel patches provided by Qualcomm and Android security teams to address the specific memory exposure issue. System administrators should also implement monitoring for unusual memory access patterns that might indicate exploitation attempts. The vulnerability highlights the importance of proper isolation mechanisms between secure and non-secure processing environments, aligning with ATT&CK technique T1068 (Local Privilege Escalation) and T1547 (Registry Run Keys / Startup Folder) as attackers could use the exposed memory addresses to escalate privileges or maintain persistent access. Additionally, security researchers recommend implementing stricter memory management controls within kernel modules and conducting regular security audits of system call interfaces to prevent unauthorized memory exposure. Organizations should also consider implementing mobile device management solutions that can detect and respond to anomalous behavior patterns that might indicate exploitation attempts.