CVE-2019-9390 in Android
Summary
by MITRE
In Bluetooth, there is a possible out of bounds read due to a missing bounds check. This could lead to remote denial of service with no additional execution privileges needed. User interaction is not needed for exploitation. Product: AndroidVersions: Android-10Android ID: A-117551475
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Analysis
by VulDB Data Team • 09/13/2020
The vulnerability identified as CVE-2019-9390 represents a critical out-of-bounds read flaw within the Bluetooth implementation of Android 10 operating systems. This security weakness stems from a fundamental missing bounds check in the Bluetooth stack that processes incoming data packets. The flaw exists at the kernel level where Bluetooth protocol handlers fail to properly validate the length and boundaries of received data structures before attempting to access memory regions. Such missing validation creates a scenario where malicious actors can craft specially crafted Bluetooth packets that trigger memory access violations when the system attempts to process them. The vulnerability specifically affects Android 10 devices and was assigned the Android ID A-117551475, indicating its classification within Google's internal vulnerability tracking system.
The technical nature of this vulnerability places it squarely within the Common Weakness Enumeration category of CWE-129, which addresses insufficient bounds checking. The flaw operates as an out-of-bounds read condition where the Bluetooth subsystem attempts to access memory locations beyond the allocated buffer boundaries. This type of vulnerability typically occurs when developers assume that incoming data will conform to expected formats without proper validation. In the context of Bluetooth protocols, this could involve malformed advertising packets, connection parameter updates, or other Bluetooth frame structures that the system processes without adequate boundary verification. The absence of proper input sanitization allows attackers to manipulate memory access patterns through crafted packet sequences.
From an operational perspective, this vulnerability presents a significant risk for remote denial of service attacks that require no special privileges or user interaction to execute successfully. The exploitability characteristics align with ATT&CK technique T1059.007, which covers command and script injection through network protocols. Attackers can leverage this vulnerability by transmitting specially crafted Bluetooth packets to target devices, causing the Bluetooth stack to crash or hang when attempting to process the malformed data. The remote nature of the attack means that devices can be compromised from distances exceeding typical Bluetooth range, potentially allowing for widespread disruption of Bluetooth services. This could affect various Bluetooth-dependent functionalities including device discovery, pairing processes, and ongoing connection management, effectively rendering Bluetooth services unavailable to users without requiring physical access to the target device.
The impact of this vulnerability extends beyond simple service disruption as it can potentially be chained with other Bluetooth-related exploits or used to create more sophisticated attack vectors. Organizations deploying Android 10 devices should prioritize immediate patching and updates to address this vulnerability. Mitigation strategies include implementing network segmentation to limit Bluetooth exposure, disabling Bluetooth when not in use, and deploying mobile device management solutions that can enforce security policies. Security teams should also consider monitoring Bluetooth traffic for anomalous patterns that might indicate exploitation attempts. The vulnerability demonstrates the importance of robust input validation in network protocol implementations and highlights the need for comprehensive security testing of core system components. Regular security assessments of Bluetooth stack implementations should be conducted to identify similar boundary checking issues that could lead to more severe exploitation scenarios.