CVE-2019-20549 in Samsung
Summary
by MITRE
An issue was discovered on Samsung mobile devices with N(7.x), O(8.x), and P(9.0) (Broadcom chipsets) software. A heap out-of-bounds access can occur during LE Packet reception in Broadcom Bluetooth. The Samsung ID is SVE-2019-15724 (November 2019).
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Analysis
by VulDB Data Team • 10/04/2020
This vulnerability represents a critical heap out-of-bounds access flaw in the Bluetooth subsystem of Samsung mobile devices running Android versions 7.x, 8.x, and 9.0 that utilize Broadcom chipsets. The issue manifests specifically during the reception of Low Energy (LE) Bluetooth packets, indicating a fundamental memory management error in the Bluetooth protocol handling code. The vulnerability is classified as a heap-based buffer overflow that occurs when the system attempts to read or write data beyond the allocated memory boundaries during Bluetooth packet processing. This type of vulnerability falls under CWE-121, heap-based buffer overflow, and represents a significant security risk that could be exploited to execute arbitrary code or cause system instability. The vulnerability was identified and tracked by Samsung under the internal identifier SVE-2019-15724, highlighting the company's recognition of the severity of the issue.
The technical flaw stems from improper bounds checking within the Bluetooth LE packet reception handling code within the Broadcom chipset implementation. When the device receives Bluetooth LE packets, the system fails to properly validate the packet size or structure before processing the data, leading to memory access violations that can result in unpredictable behavior. This memory corruption can occur in the heap memory region where Bluetooth packet buffers are allocated, allowing attackers to potentially overwrite adjacent memory locations or trigger memory corruption that could lead to privilege escalation. The vulnerability is particularly concerning because Bluetooth LE is a widely used protocol for connecting various peripheral devices such as headphones, fitness trackers, smartwatches, and IoT devices, making the attack surface broad and accessible through legitimate device pairing scenarios.
The operational impact of this vulnerability extends beyond simple device instability, as it represents a potential pathway for remote code execution attacks. An attacker within Bluetooth range could potentially craft malicious LE packets that trigger the heap overflow condition, potentially leading to complete system compromise. This vulnerability aligns with ATT&CK technique T1059.007 for command and script interpreter usage, as successful exploitation could enable attackers to execute arbitrary commands on the affected device. The risk is particularly elevated for devices that automatically pair with unknown Bluetooth devices or maintain active Bluetooth connections, as these scenarios provide multiple attack vectors for exploitation. The vulnerability affects a significant portion of Samsung's smartphone lineup, particularly those using Broadcom Bluetooth chipsets, making it a widespread concern across the Android ecosystem.
Mitigation strategies for this vulnerability should prioritize immediate software updates from Samsung, as the company would have released security patches addressing the heap overflow condition. Organizations and users should implement Bluetooth security best practices including disabling Bluetooth when not in use, maintaining device security updates, and employing Bluetooth device whitelisting where possible. The fix would typically involve implementing proper bounds checking in the Bluetooth LE packet processing code, ensuring that all incoming packet data is validated before memory allocation and processing occurs. Additionally, network segmentation and Bluetooth security monitoring should be implemented to detect potential exploitation attempts. This vulnerability demonstrates the critical importance of Bluetooth security in mobile devices and highlights the need for comprehensive security testing of wireless communication protocols, particularly those handling real-time data streams from peripheral devices.