# Attack Categorisation for IoT Applications in Critical Infrastructures, a Survey
## 4 Attack Categorisation
### Objective Oriented  
A different method for attack categorisation is organisation based on the objective of the specific attack. For example, complementary to their categorisation based on the Access Type presented previously, ref. [16] used the notion of _Privacy_, where they enumerated attacks that recover private information through various spying techniques. These attacks are even more significant depending on the environment in which they reside as the quantity of information varies, for example in an IoT-based smart home, such attacks can recover large quantities of data, encrypted or otherwise for later analysis and exploitation [63]. In [20], the authors complement their already large categorisation methods with the addition of eight independent objective oriented categories: _Reconnaissance_, _Access_, _Malicious_, _Non-Malicious_, _Cyber Crime_, _Cyber Espionage_, _Cyber Terrorism_, and finally _Cyber War_. As presented previously in Section 3.1.1, _Reconnaissance_ attacks are the first step towards the realisation of a cyber attack, recovering information concerning the target or its environment. The notion of _Access_ attacks on the other hand, as their name states, concern all attacks that attempt to gain unauthorised access to a device. The next two compose two vast categories capable of encompassing all attacks. Simply put, _Malicious_ attacks are deliberate attempts to compromise a system, generally providing an advantage to the attacker, whereas _Non-Malicious_ attacks are generally the result of accidental damage or mishandling, causing various degrees of difficulties for system operations. The next four categories concern various degrees of malicious behaviour in the cyber space. The first, _Cyber Crime_ covers small attacks where the goal was for the attackers personal gain. Above this, we can find _Cyber Espionage_, which concerns any spying activities where information recovery is the primary objective. Following on, the next level called _Cyber Terrorism_ encompasses any attacks that cause significant damage and disruption to both people and property. Finally, the highest threat level is _Cyber War_, which, in this case,concerns attacks between nations, where the nation itself is the attacking entity aiming to gain significant advantages over their victim. Following on from previously, in [44], three more categories complement their three existing attack-type-oriented approaches: _Disconnection and Goodput Reduction_, _Side-Channel Exploitation_, and _Covert-Channel Exploitation_. The first grouping impacts the efficiency of the network connection itself. It, therefore, contains attacks that aim to disconnect devices from the network, stopping them from communication, or by severely impacting and reducing the operational efficiency, called Goodput [64]. Other than impacting network operations, it is possible to use other methods to extract important information regarding internal device operations. In the case of cryptosystems, using _Side-Channel_ or _Covert-Channel Exploitation_. Contrary to its _Side-Channel_ sibling, which was previously defined, _Covert-Channels_ exploit weaknesses in the device configuration where authorised information is shared between two cooperating entities, all the while breaching security policies [65]. In [57], the position of the attacker is mentioned when presenting the various possible attacks. However, they also identify three areas where an attack impact is generally targeted, including an often overlooked aspect: _Hardware_, _Network_, and _Human Factor_. When it comes to Hardware-related attacks, there are many different approaches to significantly impact or exploit the various devices hardware characteristics. For example, Side-Channel attacks as well as malicious software that take advantage of certain device specifications to severely impact or destroy the hardware itself Network attacks, however, cover the many different methods used to impact various different network services by taking advantage if the various characteristics.