CVE-2019-9396 in Android
Summary
by MITRE
In Bluetooth, there is possible controlled termination 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-115747155
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Analysis
by VulDB Data Team • 09/13/2020
The vulnerability identified as CVE-2019-9396 represents a critical flaw in the Android Bluetooth implementation that exposes devices to remote denial of service attacks. This issue stems from a missing bounds check within the Bluetooth stack, specifically affecting Android 10 operating systems. The vulnerability resides in the Bluetooth subsystem's handling of certain packet structures where insufficient validation allows malicious actors to craft specially formatted data that can trigger unexpected behavior in the Bluetooth protocol processing layer.
The technical nature of this flaw falls under CWE-129, which encompasses implementations that fail to perform proper bounds checking on array indices or buffer sizes. In the context of Bluetooth communications, this missing validation allows an attacker to send malformed packets that cause the Bluetooth service to terminate unexpectedly. The vulnerability does not require any special privileges or user interaction for exploitation, making it particularly dangerous as it can be triggered remotely over the air without the need for physical access or user consent. This characteristic aligns with ATT&CK technique T1059.007, which covers the use of remote code execution capabilities through network protocols.
The operational impact of this vulnerability extends beyond simple service disruption, as it can effectively render Bluetooth functionality unusable on affected Android devices. When exploited, the controlled termination can cause the Bluetooth service to crash repeatedly, preventing users from connecting to Bluetooth devices such as headphones, keyboards, or other peripherals. This denial of service affects core device functionality and can potentially impact emergency communication scenarios where Bluetooth connectivity is critical. The vulnerability affects all Android 10 devices and represents a significant security gap in the mobile platform's wireless communication stack.
Mitigation strategies for this vulnerability should focus on immediate patch deployment through Android security updates, as Google released fixes in their regular security bulletins. Organizations should implement network monitoring to detect unusual Bluetooth termination patterns that might indicate exploitation attempts. Device administrators should also consider disabling Bluetooth when not in use and implementing network segmentation to limit potential attack vectors. The fix typically involves adding proper bounds checking mechanisms to validate packet sizes and buffer limits before processing Bluetooth protocol data, ensuring that all incoming Bluetooth frames conform to expected parameters and preventing the exploitation of the unchecked array access that leads to service termination.