We investigate Apple's Bluetooth Low Energy (BLE) Continuity protocol, designed to support interoperability and communication between iOS and macOS devices, and show that the price for this seamless experience is leakage of identifying information and behavioral data to passive adversaries. First, we reverse engineer numerous Continuity protocol message types and identify data fields that are transmitted unencrypted. We show that Continuity messages are broadcast over BLE in response to actions such as locking and unlocking a device's screen, copying and pasting information, making and accepting phone calls, and tapping the screen while it is unlocked. Laboratory experiments reveal a significant flaw in the most recent versions of macOS that defeats BLE Media Access Control (MAC) address randomization entirely by causing the public MAC address to be broadcast. We demonstrate that the format and content of Continuity messages can be used to fingerprint the type and Operating System (OS) version of a device, as well as behaviorally profile users. Finally, we show that predictable sequence numbers in these frames can allow an adversary to track Apple devices across space and time, defeating existing anti-tracking techniques such as MAC address randomization.

翻译：我们调查苹果公司的蓝牙低能(Blue牙)连续性协议,目的是支持iOS和macOS设备之间的互操作性和通信,并表明这种无缝经验的价格是将识别信息和行为数据泄漏给被动对手。 首先,我们反向工程设计许多连续性协议电文类型,并查明未加密传输的数据字段。我们显示,根据锁定和打开设备屏幕、复制和粘贴设备屏幕、制作和粘贴电话信息、在打开时窃听屏幕等行动,连续信息被反复播放。实验室实验揭示了最新版本的MacOS系统存在重大缺陷,它完全通过让公众MAC地址广播,完全挫败了MAC(MAC)访问控制(MAC)地址的随机化。我们证明,可以使用连续性信息的格式和内容对设备的类型和操作系统版本以及行为简介用户进行指纹。最后,我们表明,这些框架中的可预知序列号可以让对手跟踪苹果设备在空间和时间上的位置,从而击败了现有的反跟踪技术,例如MAC地址随机化。