CVE-2018-5905 in Android
Summary
by MITRE
In all android releases (Android for MSM, Firefox OS for MSM, QRD Android) from CAF using the linux kernel, a race condition while accessing num of clients in DIAG services can lead to out of boundary access.
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Analysis
by VulDB Data Team • 05/17/2023
The vulnerability identified as CVE-2018-5905 represents a critical race condition flaw within the Diagnostic services of Android-based systems developed by Qualcomm Atheros. This issue affects multiple Android variants including Android for MSM, Firefox OS for MSM, and QRD Android platforms that utilize the Linux kernel as their underlying operating system. The fundamental problem occurs during the dynamic management of client connections within the DIAG subsystem where concurrent access patterns create opportunities for improper memory handling. The race condition specifically manifests when the system attempts to access and update the count of active clients while other processes or threads may simultaneously modify or reference this same value, leading to unpredictable behavior.
The technical implementation of this vulnerability stems from insufficient synchronization mechanisms within the DIAG services kernel module. When multiple processes attempt to register or unregister client connections simultaneously, the counter tracking the number of active clients becomes inconsistent. This occurs because the increment and decrement operations on the client count variable are not properly protected by atomic operations or mutex locks. The flaw allows attackers to manipulate the client count in ways that can cause the system to access memory locations beyond the allocated buffer boundaries. This out-of-bounds memory access can result in system instability, potential privilege escalation, or even complete system compromise depending on the execution context.
From an operational perspective, this vulnerability poses significant risks to mobile device security and system integrity across various Qualcomm-powered devices. The race condition can be exploited by malicious applications or attackers with local access to the device, potentially leading to denial of service conditions, data corruption, or unauthorized system access. The impact extends beyond individual device security as it affects entire platform ecosystems including automotive infotainment systems, IoT devices, and mobile communication infrastructure that rely on Qualcomm's Android implementations. The vulnerability's presence in multiple Android variants means that security patches must be coordinated across several software components and device manufacturers, creating complexity in remediation efforts.
The weakness aligns with CWE-362, which specifically addresses race conditions in software implementations, and can be mapped to ATT&CK technique T1068, which covers local privilege escalation through system vulnerabilities. This vulnerability demonstrates the critical importance of proper synchronization in kernel-level operations and highlights the need for comprehensive testing of concurrent access patterns in embedded systems. Organizations should implement immediate mitigations including applying available security patches from device manufacturers, implementing runtime monitoring for abnormal client count behaviors, and conducting thorough security assessments of diagnostic services across affected platforms. Additionally, developers should adopt defensive programming practices including atomic operations, proper locking mechanisms, and comprehensive unit testing of concurrent code paths to prevent similar vulnerabilities in future implementations.