# Security Threats and Cryptographic Protocols for Medical Wearables
## 2 Security in Medical Devices
### Communication Protocols  
WHMS usually transmit the measured data to database servers, update their configuration using a concrete smartphone app, and communicate with other devices for different purposes. These communications protocols are principally based on BLE, RF, or Wi-Fi [34], and the little attention given to these transmission options have created a critical attack vector. For example, in [48] two successful attacks against an insulin pump are executed by reverse engineering the wireless communication protocols of the delivery system. One of the attacks was passive and allowed to eavesdrop on the signals and obtain information of the insulin pump, such as the commands that it received. The second attack was active,and enabled the adversary to remotely control the insulin pump. Similar attacks are shown in [49].  
In [50], [PERSON] et al. construct FitBite, a tool that exploits the vulnerabilities of the medical tracker Fitbit, and attack this device tracking private data, injecting and modifying the measured data in real time, and replaying the user's account data. They demonstrated how these actions could be used to conduct DoS attacks, collapsing the functioning and draining the battery of the device. Another example of the vulnerability of BLE is included in [35], where the authors examine the security of nine different fitness trackers and explain the vulnerabilities of their communication protocols. In fact, they are able to eavesdrop and manipulate measured data and change the configuration of the devices, performing DoS attacks without changing any source code.  
In 2016, several articles, such as [51; 52; 53], were published and demonstrated that BLE and Wi-Fi connections are vulnerable to eavesdropping, brute force, and man-in-the-middle (MITM) attacks. These attacks were performed on devices available in the market, such as Fitbit, Jawbone UP, Samsung smartwatches, and Pebble Watch. Apart from Fitbit, Xiaomi Huami, and Samsung Gear3 were also attacked in [54]. Although this work recognize security improvements in the Samsung Gear3, the authors are able to use the BLE connections of the wearables to eavesdrop on the information and track the identity of the patients.  
[PERSON] et al. [55] proposed a method based on Shannon entropy tests and Chi-squared tests to collect network traffic from WHMS, detecting plain messages transmission of the packet payload and compromising the security of sensitive medical information of the patients. [PERSON] et al. [56] analyzed in their research the safety of the transport layer security (TLS) protocol in 25 mHealth Android applications. Their results indicate that the majority of them present weak TLS configurations and are susceptible to MITM attacks. BLE communications between wearable devices and smartphone apps, and between these apps and servers using the Internet were examined in [57]. The authors found that these communications were not secure, sending patients credentials in clear text and allowing connections with unbounded devices. A work by [PERSON] et al. [58] uses unmanned aerial vehicles to interrupt Bluetooth and Wi-Fi data transmission of WHMS, leading to data interception, data corruption, and service unavailability (DoS).  
The research presented in [59; 60] execute eavesdrop, replay and DoS attacks on wearable devices, but also propose new tools based on Artificial Intelligence (AI) to find anomalies in the devices' functioning, create an intrusion detection system, and protect the wearables.