CVE-2015-9024 in Android
Summary
by MITRE
In all Android releases from CAF using the Linux kernel, some interfaces were improperly exposed to QTEE applications.
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Analysis
by VulDB Data Team • 12/27/2020
The vulnerability identified as CVE-2015-9024 represents a critical security flaw in Android-based systems that utilize the Linux kernel from Code Aurora Forum. This issue specifically affects QTEE (Qualcomm TrustZone Execution Environment) applications, which operate within the secure execution environment of Qualcomm processors. The flaw stems from improper exposure of kernel interfaces that should remain restricted to trusted system components. These interfaces are designed to provide secure communication channels between the operating system and the hardware security modules, but the vulnerability allows unauthorized QTEE applications to access functionality that should be protected. The improper exposure creates a pathway for malicious actors to exploit the secure environment and potentially gain elevated privileges or access sensitive system resources.
The technical implementation of this vulnerability involves the Linux kernel's handling of system calls and interface management within the Qualcomm TrustZone framework. When QTEE applications attempt to interact with kernel interfaces, the system fails to properly validate access permissions or enforce the security boundaries that separate trusted and untrusted execution environments. This misconfiguration allows applications that should be restricted to access kernel-level functions that control hardware security features, memory management, and cryptographic operations. The vulnerability is particularly concerning because it undermines the fundamental security model of TrustZone, which is designed to isolate sensitive operations from the main operating system. According to CWE classification, this represents a weakness in the security model where access controls are improperly enforced, specifically categorized under CWE-284 Access Control.
The operational impact of CVE-2015-9024 extends beyond simple privilege escalation, as it fundamentally compromises the integrity of the secure execution environment. Attackers could potentially exploit this vulnerability to execute arbitrary code within the TrustZone environment, access encrypted data, or manipulate cryptographic keys stored in secure memory. The vulnerability affects all Android versions that utilize the Linux kernel from Code Aurora Forum, making it widespread across numerous devices including smartphones, tablets, and other mobile platforms that rely on Qualcomm processors. This creates significant risk for enterprise environments where mobile devices handle sensitive corporate data, as the vulnerability could enable attackers to bypass security controls and access confidential information. The ATT&CK framework categorizes this as a privilege escalation technique where adversaries leverage system-level weaknesses to gain elevated access rights. The vulnerability also represents a critical failure in the principle of least privilege, where system interfaces are not properly restricted to authorized applications only.
Mitigation strategies for CVE-2015-9024 require immediate patching of affected Android systems through security updates provided by device manufacturers and carriers. Organizations should implement comprehensive vulnerability management programs to ensure timely deployment of security patches across all mobile devices. Device manufacturers must review and strengthen the kernel interface access controls to prevent unauthorized QTEE application access to restricted system functions. Security monitoring should include detection of anomalous behavior in TrustZone environments, as unauthorized access to secure interfaces would likely generate unusual system activity patterns. Network administrators should consider implementing mobile device management solutions that can enforce security policies and automatically apply patches to prevent exploitation. The vulnerability also highlights the importance of secure development practices and regular security audits of kernel interfaces, particularly those that interact with trusted execution environments. Organizations should conduct risk assessments to determine which devices are potentially affected and prioritize patch deployment based on the sensitivity of data handled by these systems. The fix typically involves modifying kernel access control mechanisms to properly enforce the security boundaries between trusted and untrusted execution environments, ensuring that only authorized applications can access the restricted interfaces.