# Security Vulnerabilities in LPWANs--An Attack Vector Analysis for the IoT Ecosystem
## 1 Introduction  
The Internet of Things (IoT) ecosystem, due to its pervasive nature, demands low-power and wide-area communications, particularly in applications, where IoT devices do not require high speed nor high bandwidth, but still need extended coverage. Generally, an IoT device is typically composed of: a sensing/actuating element; a small-sized battery; a low-cost microprocessor (typically a microcontroller); limited memory; and a radio module that enables low-power wireless communications. When operating, the power budget of an IoT device is mostly affected by the computing and communications tasks. This means that to increase the autonomy of an IoT device, the reduction of the computational cost and the minimization of the communication load (mainly affected by the duration and duty-cycle of data transmission, and the available bandwidth) must be a priority. Reducing the computational cost can be achieved by selecting state-of-the-art ultra-low-power microprocessors and by using event-triggered programming techniques, such as Wake-on-Interrupt (WoI) [1] or Wake-Up-Radio (WUR) [2, 3], and by forcing the microprocessor into an ultra-low-power \"sleep\" state, until a WoI or WUR event occurs. Thesestrategies can considerably reduce the overall CPU execution time and therefore contribute to more efficient power management of the IoT devices. Reducing the communications power consumption can be achieved by using specific wireless communication technologies, such as Low Power Wide Area Networks (LPWAN), which represents a class of wireless technologies that have been designed for the specific needs of Machine-to-Machine (M2M) communications and the Internet of Things. LPWANs are typically used with resource-constrained IoT devices, with a focus on intermittent communications with long duty-cycles (minutes, hours, days) contributing to a huge reduction of power in the transmission task. Battery-efficient IoT devices can operate reliably for up to 10 years [4; 5] on a single battery charge and perform long-range wireless communication at a regional/city level. Figure 1 depicts a set of IoT devices used in multiple application scenarios, for example, authentication using RFID [6], to a bike with a tracking device, using a LoRa network [7; 8]. These IoT devices are deployed at different communications ranges from their gateways and, in the case of the IoT devices using long-range distances, they must use efficiently the computational and communications resources. When compared with other technologies, cf. Figure 2, LPWANs present higher cost-benefit and higher power/bandwidth efficiency for long-range communications, which results in less infrastructure/hardware needs. By using LPWAN technologies, communications become less dependent on common existing infrastructures--for example, Wi-Fi, which is widely available but presents major drawbacks such as high power consumption and short-range communications--enabling IoT devices to operate on small and inexpensive batteries, and be easily deployed within a wide area, typically more than 2 km in urban zones [9]. Figure 1: Communication Technologies in IoT applications by range. Mobile networks like 3G and LTE deliver high-speed Internet access [11]. This type of communication is characterized by a high battery drain and flaws in coverage which, according to [12], does not prove to be suitable for the IoT ecosystem. Consequently, cellular networks are not handy for M2M or local network communication [13]. Zigbee is a worldwide standard for low-power mesh networks with enhanced security features, built on top of the IEEE 802.15.4 standard, that has been mainly used in home automation and smart building applications [14]. However, Zigbee operates on private networks [15; 16; 17], and has not been designed for long-range communications--only for small-scale projects (10-75 m) [18]--but rather to implement mesh networks. In its turn, mesh networks suffer from many factors, such as limited network coverage and high response time [19].