Keywords

1 Introduction

IoT emerged in the year 1999 with the introduction of Wireless Sensor Networks (WSN) and technologies like Radio-Frequency Identification (RFID). The concept behind the IoT is to connect everything to anything, anywhere, and at any moment of time. For making physical or virtual connections, it uses objects like sensors, actuators, etc. The success of IoT infrastructure and applications depends on IoT security. IoT collects the data from a vast geographical region using sensors and actuators [1].

The IoT is going to gain the attention of masses. The concept of IoT devices is not only about providing connectivity but also they need to be interactive. The need of hour is that they should deploy context-based interactions [2]. There will be billions of interconnectivity among the internet that will surely open doors for hackers and with that there will be a lot of security and privacy threats that will need immediate supervisions.

The objective of IoT technology is to provide interconnections between humans, things, and between humans and objects. In the IoT infrastructure, the sensors and objects are integrated for communications that can work successfully without human interventions. The sensors play an important role in IoT as these devices not only collect heterogeneous data but also monitors the data with diversity and is quite intelligent and dynamic in nature [3, 4]. The major IoT principles include confidentiality, authentication, availability, heterogeneity, lightweight solutions, key management, policies, and integrity.

IoT has a layered structure where each layer provides a service. Usually, the IoT architecture is categorized in three layers, namely, application, network, and perception layer. The security issues like privacy, authorization, verification, access control, system configuration, information storage, and management that are the real challenges of the IoT infrastructure [5, 6]. The security needs vary from layer to layer as each layer serves a different purpose [5]. Undoubtedly, to make IoT a reality the security issues need to be resolved. There are two types of security challenges, namely, technological and security challenges. The technological challenges include wireless technologies and the distributed nature of the IoT. The challenges related to authentication and confidentiality included in the security [7].

This paper discusses the protocols present on different IoT layers and identify the security threats at each layer. Different security issues and its countermeasures have been discussed in detail. The objective of this paper is to enlighten the essential security protocols of IoT that obliging for the prevention of harmful threats.

2 IoT Architecture

IoT has a three-layered architecture. The three layers are as follows:

  • The Application Layer,

  • The Network Layer, and

  • The Perception Layer.

The Application Layer: The main aim of the application layer is to deliver specific services to its users [8]. It defines numerous applications of IoT, viz., smart home, health, cities where it can be deployed.

The Network Layer: This layer is most prone to attacks, it aggregates data from existing infrastructures and transmits the data to other layers. It processes the sensor data. The major security issues usually related to authentication and integrity of data that is being transmitted [9].

The Perception Layer: This is the physical layer, even known as the lowest layer of the IoT architecture and reflected as a brain of the three-layered architecture. The sensing devices like the sensors and actuators are present at this layer. This layer is also known as the sensor layer [10, 11] (Tables 1 and 2).

Table 1 Different protocols that are present on different layers
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Table 2 Application, network, and perception layer protocols
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3 Security Requirements

IoT infrastructure consists of a lot of personal information such as name, date of birth, locations, etc. Therefore, we need to provide strict measures to protect the data and tackle privacy risks. In order to overcome the security challenges, the layered structure is adopted. The basic security properties that need to be implemented are confidentiality, authenticity, integrity, and availability. There are a number of other security requirements that are derived from the basic security requirements such as scalable, IP Protocol-Based IoT, Heterogeneous IoT, and Lightweight Security.

4 IoT Security Threats

The threats can broadly be classified into three categories. The categories are capture, disrupt, and manipulate. The capture threat means capturing information or system without authorization. The capture threats are such threats that are designed to gain access of information that is either logical or physical on a system. The disrupt threat means denying access or destroying a system. The manipulated threat means manipulating time series data, identity, or the data (Table 3).

Table 3 The description of threats at each layer
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5 IoT Challenges

Due to the vast scale of IoT infrastructure with a huge number of devices involved in developing a successful IoT application is not an easy task and have to face a lot of challenges. Some of the challenges are, namely, mobility, reliability, availability Identification, scalability, data integrity, management, energy management, interoperability, and security and privacy.

Mobility: It is one of the essential issues of the IoT paradigm. As IoT devices move freely from one network to another, therefore, movement detection is important to monitor the device location and respond to the topology that changes accordingly due to which layer of complexity escalate to another level [25].

Reliability: Reliability is a very critical requirement in the application that requires all the emergency responses correctly otherwise, it will be a huge disastrous scenario. In IoT applications, data collection, communication should be fast and highly reliable [25].

Scalability: Other challenges of IoT application is scalability, where enormous number of devices are connected to a network, therefore, the protocols must have efficient extensible services to meet the IoT devices requirements [26].

Management: Managing a vast number of devices and keeping track of their failures, configurations, and performances in the network is an immense challenge [26].

Energy management: In IoT devices, energy is required still not adequately met. Some routing protocols at an early stage of development supports low power communication but to make IoT devices more power efficient, Green technology must be employed [25].

Availability: Availability means the service subscriber provides the service anytime and anywhere for the service subscribers. Software service provided to anyone who is authorized to, whereas the hardware availability means easy to access and are compatible with IoT functionality and protocols.

Interoperability: Huge number of heterogeneous devices and protocols work with each other. This becomes a challenging task due to the number of IoT devices using various platforms [25].

Identification: To provide innovative services, the IoT devices are interconnected with numerous objects, and hence, an efficient naming and identity managing system is required to specify the object [26].

Data Integrity: IoT devices are heterogeneous in nature, therefore, they have to deal with big amount of data. Handling big data is very crucial as overall the performance is directly proportional to the features of data management services. Became more complicated when data integrity features are considered, it also affects the QoS, Privacy, and Security related issues specifically on outsourced data [25, 26].

6 Counter Measures

The countermeasures that can be taken are the authentication measures, establishment of trust, and acceptance of federated architecture awareness of security issues (Table 4).

Table 4 The countermeasure of threats at each layer
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7 Conclusion

IoT has recently emerged as an important research topic. Due to emerging technology attackers take advantages of the IoTs great potential to threaten users privacy, security, and wide variety of attacks. Therefore, it is essential to focus on the security parameters and heeded toward giving new feasible solutions to block all possible threats and vulnerabilities to IoT. This paper presents a comprehensive overview of security threats and attacks on IoT. Application, network and perception layer protocols with purpose been discussed. In addition, this paper suggested several countermeasures against identified security threats of each layer.

A lot more need to happen in near feature in the area of IoT applications. This IoT field will definitely mature the impact of human life in inconceivable ways over the next decades. As IoT is going to play an indispensable part in our lives, steps should be taken to ensure the security and privacy of the users.

Future work involves finding alternative solutions for attacks that are less complex and less time-consuming. Future research involves development of protocols and finds ways to overcome security threats and attacks.