CVE-2018-5849 in Android
Summary
by MITRE
Due to a race condition in the QTEECOM driver in all Android releases from CAF (Android for MSM, Firefox OS for MSM, QRD Android) using the Linux Kernel, when more than one HLOS client loads the same TA, a Use After Free condition can occur.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 02/18/2020
The vulnerability identified as CVE-2018-5849 represents a critical race condition within the QTEECOM driver component of Android systems developed by Qualcomm Atheros. This flaw exists in the Linux kernel implementation across multiple Android variants including Android for MSM, Firefox OS for MSM, and QRD Android platforms. The fundamental issue arises from insufficient synchronization mechanisms within the driver's memory management processes, creating an exploitable window where multiple high-level operating system clients can simultaneously access and manipulate the same Trusted Application (TA) instance.
The technical execution of this vulnerability stems from a classic use-after-free condition that occurs when multiple HLOS (High Level Operating System) clients attempt to load identical Trusted Applications concurrently. When the QTEECOM driver manages these simultaneous loading operations without proper mutual exclusion controls, it can result in memory deallocation followed by subsequent access to the same memory region. This race condition creates a scenario where one client may free a TA instance while another client attempts to use it, leading to potential memory corruption and arbitrary code execution privileges. The vulnerability specifically affects the Trusted Application loading mechanism within the Qualcomm Trusted Execution Environment (TEE) framework.
From an operational standpoint, this vulnerability presents a significant security risk as it allows for privilege escalation and potential system compromise. Attackers can exploit this condition to execute malicious code with elevated privileges typically reserved for trusted system components. The impact extends beyond simple memory corruption, as the use-after-free condition can be leveraged to overwrite critical memory structures, potentially enabling full system compromise. The vulnerability affects all Android releases utilizing the affected Qualcomm kernel components, making it particularly concerning for widespread deployment across various mobile devices and embedded systems.
The mitigation strategies for CVE-2018-5849 require immediate patching of the affected kernel components and implementation of proper synchronization mechanisms within the QTEECOM driver. System administrators should prioritize updating to patched kernel versions that address the race condition through appropriate mutex or semaphore implementations. Additionally, the vulnerability aligns with CWE-362 which specifically addresses race conditions in concurrent programming, and relates to ATT&CK technique T1068 which covers privilege escalation through kernel exploits. Organizations should also implement runtime monitoring to detect anomalous TA loading patterns and consider device hardening measures including disabling unnecessary TA loading capabilities and implementing strict access controls for trusted application interfaces.