# Comprehensive Review of UAV Detection, Security, and Communication Advancements to Prevent Threats
## 7 Current Vulnerability Issues of UAVs  
For these UAVs, unfortunately, there is neither a standardization of policies nor the availability of wireless security [42; 43; 44]. This leads to several threats, as highlighted in Table 5. There are researchers who have addressed different types of cyber-attacks associated with the several types of UAVs in a pre-controlled environment [45; 46; 47; 48; 49; 50]. Such practical validations include the crashing of drones with many parallel requests and modifying the request packet known as the buffer-overflow attack, whereas some researchers went for the cache-poisoning approach that leads to the shutdown of communication between the drone and GCR. In all conditions, most attacks occur to target the operating system or, in other words, the microcontroller of the drone [51]. Since there are huge advancements in the technology, UAVs have a high probability of experiencing such attacks, as shown in Figure 9 [52; 53; 54; 55; 56; 57; 58]. From these attacks, the most common attack is GPS spoofing, such as signal jamming, de-authentication. and zero-day attacks.  
\begin{table}
\begin{tabular}{c p{142.3 pt}} \hline \hline
**Vulnerability Type** & **Description** \\ \hline \multirow{4}{*}{Malware issue} & In various cases, it has been observed that these UAVs are generally connected and controlled via cell phone or any sort of remote control. These techniques are, thus far, not safe [43] and, therefore, the UAVs are easy to be hacked using a reverse-shell TCP payload that can be injected into UAV memory. \\  & Furthermore, this leads to installation of malware over UAVs automatically. \\ \hline \multirow{4}{*}{Spoofing} & These are the issues related to the communication method, usually with serial port connections that are not encrypted properly [44]. Due to this spoofing issue, the information associated with GPS can be taken and altered. \\ \hline \multirow{4}{*}{Manipulation and other common concerns} & The flying paths which UAVs must track are pre-programmed before; therefore, these paths can be altered [45], whereas the common issues are related to wind, overheating, or any predator bird harming the lightweight drone easily [46]. \\ \hline \multirow{4}{*}{Physical design and control system constraints} & There are various challenges with unmanned aerial vehicle control system design, such as the sluggish convergence rate, which prevents the drone from performing fast or aggressive maneuvers, and one may notice faults in the flight or divergence from the target trajectory [47; 59; 60]. This slow convergence rate and glitches are caused by the physical architecture of drones or the planned control system, which is primarily intended to stabilize the drone in uncertain conditions. \\ \hline \multirow{2}{*}{Sensorization issue} & Since these UAVs depend on sensors, thus, it is also proved that the ultrasonic waves may attack the MEMS gyro sensors [47]. \\ \hline \multirow{2}{*}{Wi-Fi constraints} & Operating drones using a Wi-Fi facility may be risky. This is proved in [48] where the connection was disrupted with the help of software and changing the control of the UAV. \\ \hline \multirow{2}{*}{GPS issue} & Automatic Dependent Surveillance–Broadcast depends on the GPS module, which is not encrypted sometimes and may lead to spoofing [49]. \\ \hline \multirow{2}{*}{Firmware issue} & The bugs available in the first prototype and first algorithm which come to the front after usage [50]. \\ \hline \multirow{2}{*}{Sky Jack-based attacks} & Sky Jack is one software used to conduct the attacks related to de-authentication of targets during control [51]. \\ \hline \multirow{2}{*}{Controller issues} & These issues are related to the operation control unit and may puzzle the controller by changing the live feed to some other video [52]. \\ \cline{1-1}  & \\ \hline \hline \end{tabular}
\end{table}
Table 5: Summary of all current vulnerability issues in UAVs.