The smart RE integrates two-way communication technology and computational intelligence across the whole energy system, from the generation to the consumption endpoints. Despite the numerous benefits, this method leaves renewable energy vulnerable to security threats, giving hackers a new opportunity to take advantage of vulnerabilities in smart renewable energy. Moreover, perpetrators target smart renewable energy since its monitoring and management rely on public solutions and Internet-based protocols. These attacks can cause both physical and financial damages, which may lead to the power system's services being disrupted. This has physical and financial effects on the functioning of the power system.
A total of 23 vulnerabilities in photovoltaic systems were discovered in the study [32], and their root causes were investigated. All of the vulnerabilities were taken from the vulnerability databases [33], [34]. These vulnerabilities include insecure communication protocols (the problems include the usage of poor encryption techniques, poor hash algorithms, and inappropriate utilization of authentication alongside encryption.), lack of access control, Lack of parameter sanitization, Backdoor and hard-coded accounts (developers frequently employ hidden and backdoor accounts for testing purposes, but they forget to delete them before a product is given to a consumer.), cross-site scripting.
The following is a list of the most well-recognized security threats that target smart IoT-based RE system, as gathered from a survey of the relevant literature [35],[36],[37],[38],[39],[40],[41],[42],[43]:
False Data Injection (FDI)
Once intruders can alter or manipulate the original measurements given by the sensors, a sort of cyberattack known as a false data injection attack can be planned, impacting the control center’s computing capacity [44], [45], [46], [47]. In this way, the adversary can tamper with the network operator's state estimation algorithms and cause them to draw incorrect conclusions[48], [49]. It can be either cyber-based or physical-based [50]. One of the most dangerous types of attacks on distributed energy resources based on false data injection is energy theft[51]. The theft is the result of a falsified meter reading that provides inaccurate information.
Table 2
Sensors in PV and Wind energy system [30]
Unit | Part | Sensing Device |
PV System | PV Array | power, current, module temperature, tracker |
Grid | Current from grid, current to grid, power to grid, power from grid, utility voltage |
Meteo mast | Wind direction, wind speed, ambient air temperature, irradiance |
Wind Turbine System | Generator | Power, Voltage, Current, status, temperature |
Converter | Voltage, current, torque, frequency, power factor, temperature, status |
Transformer | Status, temperature, voltage, current, oil level |
Rotor | Status, rotor speed, rotor position, pitch angle, pressure temperature |
Transmission | Status, pressure, grease level, temperature, vibration, oil level |
nacelle | Status, wind speed, wind direction, orientation, displacement |
yaw | Temperature, speed, position, grease level |
meteorological | Humidity, temperature, pressure, wind speed, wind direction |
The reading from the smart meter must be precise because it is used for billing and accounting. Customers who aren't trustworthy could give false information to get a discount or ask for a high payment [52]. The effects of the FDI were investigated in [53]. The overvoltage and its effects on the grid-connected PV were brought on by the successful attack that altered sensor readings at the level of the PV system. The authors presented the economic impact of the attack as well.
Investigation of a power system integrity compromise is presented in [54]. The article [55] presented a scenario in which an FDI attack is carried out on PV system meter data being utilized for fifteen-minute forecasting. As a result of the attack, the command-and-control center provided the grid with the incorrect operational parameters, and the research shows that the FDI could lead to catastrophic failures. To solve this problem, research [56] suggests a novel FDI attack detection technique suitable for power grids with a high proportion of renewable energy sources. Using multiple attack scenarios, the created framework is tested on an IEEE 14-bus system incorporating numerous renewable energy sources. The proposed detection method performs better in a renewable energy grid-connected setting, according to numerical findings. The authors of [57] proposed a detection technique for PV grid-connected systems' voltage sensors' measurement change. Encryption techniques have generally been shown to offer significant advantages for FDI attack prevention [58], [59], [52], [60]. Unfortunately, these approaches still have a considerable computational cost. Hence, additional study is required to decrease lower computational costs, as well as improve the algorithm's efficiency, precision, and processing speed.
Man-in-the-Middle (MITM)
As part of a MITM attack, an intrusive party inserts itself into a dialogue taking place between two communicating devices to either pose as one of the devices or eavesdrop, making it seem as if the information is being exchanged normally [61]. Consequently, false command injections and false data injection assaults by the attacker might endanger power system activities including load forecasting, automatic generation management, economic dispatch, and state estimation. The Metasploit framework is used in work [62] to conduct a man-in-the-middle cyberattack on a PV plant that is connected to the grid. In [63], it is shown that a MITM assault on a power factor correction unit may overwhelm a distributing feeder, resulting in the deliberate tripping of the whole feeder as well as a subsequent blackout throughout a wide area. To show the efficacy of this approach, an experiment was implemented in a laboratory model utilizing commercial power equipment with varying loading situations. The study [64] shows that a commercial PV inverter that offers auxiliary services to the grid may be the target of a MITM attack, resulting in the deliberate collapse of the whole feeder and the subsequent blackout of a large area. The attack's efficacy and potential danger were exposed by its successful experimental execution. PV inverter capability and feeder loads are only two of the many variables taken into account to determine the overall viability of the planned attack.
Replay
Replay attacks take place when an attacker captures network traffic and acts as the main source by forwarding it to the target [18]. The threat actor either causes a delay in the data transfer or causes it to be retransmitted. An attacker can impersonate the legitimate sender of data by resending it to its intended recipient after intercepting it. The recipient of the legitimate communication is duped into thinking it was delivered from a trusted source. The message is delivered twice, which is why it is termed a replay assault. The cybercriminal who launches a replay attack doesn't even need to decode the message they're resending, making it all the more dangerous. But they can still trick the recipient into thinking the communication is genuine. Cybercriminals can gain access to otherwise inaccessible data by using networks that have been compromised through replay attacks. Replay attacks were identified as one of the attacks on renewable energy systems by the authors [65]. One of the most popular protocols for IoT devices, ZigBee, is used to transmit data between devices via a network. However, the study [66]showed that ZigBee is vulnerable to replay attacks, and the authors showcased a replay attack method that can be executed with just an open-source KillerBee and the commercially available API-Mote. Messages sent across ZigBee gadgets can be recovered with the help of a suggested noise-removal approach. The HMAC-MD5 technique was proposed by [67] as a means of detecting replay attacks in the isolated smart grid. Research [68] described a new authentication technique that combines robust cryptography with a random key method for maximum security. The study demonstrates that it has the potential to provide mutual anonymity, authentication, forward and reverse security, and resilience to replay attacks.
Denial of service (DoS): Routing protocols and electronic movements are the primary targets of DoS attacks, which overload communication channels and slow down network speeds. By overwhelming the system with extra data packets, a denial-of-service attack can effectively restrict what regular users can do [69]. In [70], two types of denial-of-service attacks were launched against the IoT-based PV system, and their performance was evaluated (in terms of both the time it took to launch the attacks and the percentage of times they were successful). The distributed denial of service (DDoS) cyberattack, in contrast, is a more severe kind of cyberattack in which several hosts attack a target simultaneously. Threat actors prepare a cyberattack ahead of time by exploiting a vulnerability to hack several hosts across communications networks; hackers then overwhelm the target site with all hacked hosts. In the case of inverter-based smart energy systems, DoS can obstruct information exchange between all devices and the control system. DDoS can be grouped into three types: volume-based [71], protocol-based DDoS [72], and application-layer DDoS [73]. The authors in [74] analyzed the impact of DOS attack on the PV system. Simulation of DOS on PV inverter is presented in [75]. The analysis of DOS impact against microgrid is presented in [76], [77], [78]. Hybrid intrusion detection system was suggested by [79] as the prevention of DOS in distributed energy resources.
Brute force credentials
The goal of this attack is to guess passwords, usernames, and encryption keys through repeated attempts and error. Before gaining access, the hacker tries several login identities and passwords. Once they're in, the criminal may stay in the system as long as no one notices that they aren't the real user. During this period, they can set up back doors, spread laterally, understand the system for the purpose of later assaults, and steal information. The optical ports of a smart meter can be accessed with brute-force password cracking using a program like termineter[80]. As a second phase of an assault, malware may be installed on the smart meter to steal the power.