CVE-2016-6539 in TrackR Bravo App
Summary
by MITRE
The Trackr device ID is constructed of a manufacturer identifier of four zeroes followed by the BLE MAC address in reverse. The MAC address can be obtained by being in close proximity to the Bluetooth device, effectively exposing the device ID. The ID can be used to track devices. Updated apps, version 5.1.6 for iOS and 2.2.5 for Android, have been released by the vendor to address the vulnerabilities in CVE-2016-6538, CVE-2016-6539, CVE-2016-6540 and CVE-2016-6541.
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Analysis
by VulDB Data Team • 12/27/2024
The vulnerability described in CVE-2016-6539 relates to a significant privacy and tracking risk associated with Trackr devices that utilize Bluetooth Low Energy technology. These devices employ a predictable identification scheme where the device ID consists of a fixed four-digit manufacturer identifier of zeros followed by the Bluetooth MAC address in reverse order. This construction creates a fundamental security flaw that directly exposes the device's unique identifier to anyone within Bluetooth range. The vulnerability represents a clear violation of privacy principles and demonstrates poor cryptographic design in the device identification system. The predictable nature of the device ID means that adversaries can easily correlate device movements and establish tracking patterns without requiring sophisticated technical capabilities or specialized equipment.
The technical implementation of this vulnerability stems from the predictable construction of the device identifier, which directly maps to the underlying Bluetooth MAC address. This design flaw creates a persistent identifier that remains constant across device sessions and can be easily harvested by attackers who are physically present in proximity to the device. The reverse ordering of the MAC address components does not provide meaningful security benefits and instead creates a deterministic mapping that adversaries can exploit. This type of vulnerability is classified as a weakness in identification and authentication mechanisms, aligning with CWE-310 and CWE-312 categories that focus on cryptographic flaws and predictable identifiers. The vulnerability directly enables location tracking and user surveillance, representing a significant privacy risk for device owners.
The operational impact of this vulnerability extends beyond simple tracking capabilities to encompass broader privacy violations and potential misuse scenarios. An attacker within Bluetooth range can not only identify the specific device but also track its movements over time, creating detailed location profiles of users. This tracking capability can be exploited for malicious purposes including stalking, unauthorized surveillance, or targeted advertising. The vulnerability affects the fundamental security model of the device, as it undermines the expected privacy protections that users would reasonably expect from a tracking device. The attack surface is particularly concerning because it requires minimal technical expertise or equipment to exploit, making it accessible to a wide range of potential adversaries. This vulnerability directly relates to ATT&CK technique T1566 which involves social engineering and physical access methods for information gathering.
The vendor response to address this vulnerability, along with related issues CVE-2016-6538, CVE-2016-6540, and CVE-2016-6541, demonstrates the importance of proper device identification design and the need for regular security updates. The release of updated applications for both iOS and Android platforms at versions 5.1.6 and 2.2.5 respectively shows that the manufacturer recognized the severity of the issue and implemented fixes to address the predictable identification scheme. These updates likely involved implementing randomized or cryptographically secure device identifiers that do not expose the underlying MAC address information. The remediation approach should have included proper entropy in device ID generation, moving away from deterministic constructions that rely on predictable physical characteristics. This vulnerability highlights the critical need for security-by-design principles in IoT devices and the importance of considering privacy implications during the development lifecycle. The resolution of this vulnerability serves as a case study in how predictable identifiers can create persistent security risks that require both software and potentially hardware-level fixes to fully address the underlying design flaws.