# Review of Smart-Home Security Using the Internet of Things
## 4 Analysis and Discussions of the IoT Setting
### Threats Faced by a Smart Home and Related Countermeasures
#### 4.2.1 Application Layer Analysis  
Attacks on an application or set of applications can cause them to malfunction, rendering them unable to perform their intended services. Several types of attacks can be carried out on such systems. One type of attack is called \"social engineering\", where the attacker targets the user directly [104; 105]. The attacker communicates with the network's legitimate administrator, often applying psychological pressure, to obtain sensitive codes that will allow them to access applications and exploit their services. Sometimes, attackers send disguised emails to deceive users into visiting websites that are replicas of legitimate ones, with the intention of stealing passwords, a tactic known as phishing. This is one of two ways in which the user can fall victim to an attack. The second approach involves the installation of malware that appears user-friendly, with the users being deceived to install the malicious software on their device [103; 106; 107]. As a result, the attacker gains complete access to the system's data and operations [108; 109], including management control. This attack typically targets devices with Internet access and can cause the entire system to crash. Today, phishing attacks are prevalent in Internet-based systems. Another form of cyber-attack involves sending malicious software to a device [39; 110; 111; 112; 113], which can either be used for phishing or to cause partial or complete system destruction. Malware, also known as worms, can be found on various websites and can infect devices running different operating systems, such as Linux. Typically, home systems are targeted, specifically their Internet-connected devices, such as cameras and routers, which can result in the collapse of a home's security system. The Mirai botnet attack is such an example, where the attacker monitors the system's activity. Ransomware is another attack where malicious code encrypts the user's data, demanding a ransom to decrypt it. This type of attack affects the last two layers of the IoT architecture and significantly impacts the behavior of the application layer. Also, crypto-jacking attacks of smart-home devices involve unauthorized use of a device's processing power to mine cryptocurrency, often resulting in lower device performance and increased electricity consumption without the user's knowledge. Another category of attack involves targeting nodes [114; 115; 116]. The aim of such attacks is to install harmful software (rootkits) on the system's devices to take control of the applications they oversee. By doing so, the attacker can alter the way the devices respond and behave, resulting in an abnormal, and often unwanted, system performance. The attacker can then impersonate an authorized user by deceiving the system, causing serious security implications. When an attacker tries to trick the system and pretend to be an authenticated user, it is considered an access control attack. This type of malicious activity targets the involved nodes of the system and can result in serious security consequences [117; 13; 118]. Unlike computers, a system's smart-devices do not automatically update/upgrade their security software [119; 120; 121]. When updating the security software on one device, there is a parallel distribution of a copy of the software to the rest of the devices in the system, with the result that for as long as this update lasts, the system is out of order. Therefore, during this time, no encryption might be required, and thus, there is an open opportunity window for attackers [122]. Unauthorized software installation from untrustworthy developers, who often disregard security protocols and standards, can create vulnerabilities that attackers can exploit to breach the security of devices [123; 124]. In the IoT realm, many devices have default settings and an operating system that lacks authentication requirements. As a result, attackers can easily gain access and modify these settings at will.