# 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
#### 4.2.2 Perception Layer Analysis  
A favorite tactic for attackers is attacking at the level of perception. As mentioned above in this paper, at the perception layer, all devices communicate, collect, and exchange data, using the sensors that each one of them possesses. In this case, the attacker tries to intercept and modify the communication software of the networking nodes, so that a device of his/her own can enter and be accepted in the network, now also receiving the sensitive information that is trafficked towards it. All devices communicate with a remote server (e.g., cloud) via the Internet. This communication is performed automatically and without particularly strong security protocols, which makes it vulnerable to third-party attacks. Thus, a device external to the network can intervene in this communication and intercept the data that the networking devices have collected and intend to send to a remote server for further processing. This attack is also known as eavesdropping [139; 140]. An alternative attack path for attackers to disable and remove sensors or devices from the network is by installing a sniffer application on them and reactivating them. They gain access through this application to the data managed by the sensors [141]. Another vulnerable point in the network is when the devices need to be restarted. Then, the system in preparation does not have time to \"run\" the security software and security protocols, such as UART or JTAG. At this moment, attackers can attack the system. These attacks are also called boot attacks [22; 117]. Most devices in a home environment often operate with low power consumption. This makes them vulnerable to attackers, who, after disabling them, can replace them with their own, \"fooling\" the network and collecting the sensitive information being trafficked towards them [141]. An attacker can even reprogram a certified device by checking its sensor, collecting all its data. Another way to intercept data is with side-channel attacks [117; 142]. These attacks are usually timing attacks, electromagnetic attacks, and laser attacks. These attacks create a parallel side channel, which steals, \"eavesdrops\" on the information exchanged by the devices' sensors in a network. This is feasible due to the low power, communication mode, and architecture followed by the sensors in an IoT system. The wireless connection and remote communication of many devices in one IoT system is carried out with the existence of noise. Noise is incomplete false irrelevant information--information, however, that may come from intruders and that can cause problems in the network [143; 144]. Noise causes the sensors to malfunction, causing them to misbehave and transmit incorrect data to end-nodes, which is a major problem for the system's security [117; 145]. The first interaction point of the system is its sensors. Sensors must be equipped with appropriate security measures in order to become resistant to attacks. Otherwise, they should not be exposed to third parties and should be kept in a safe place. At this level, the sensors are the target of attacks. Thus, the proposed solutions involve protecting the data collected and exchanged between the sensors. To mitigate the relevant attacks, various sensor interconnection and operation models are proposed, covering sniffing, path loss, shadow fading, and Rayleigh fading detection. Firstly, to protect the system from eavesdropping and sniffing, the system should run on a private and not on a public and free network, where an attacker may have easy access. On many occasions, attackers create private networks with names of public entities in order to trick users into connecting to them. Also, a device integrated in an IoT system should operate with encrypted code techniques. The device should run software from a trusted and certified developer and work with Original Equipment Manufacturer (OEM) hardware.