# Security Challenges in Industry 4.0 PLC Systems
## 2 Risk Management
### Identification of Threats and Vulnerabilities  
The greatest threat to the industrial network of a plant is humans. The number of real-life examples serve as proof. The most common method of hacking into a company's network is taking over the employee's authorization path (login and password) [66]. Technological issues and the industrial process itself are also important. The more dispersed the network structure, the more potential points of unauthorized access to it. Therefore, from the point of view of cybersecurity risk analysis, the designed security should be matched to industrial technologies and their architecture [67]. First of all, the scope of the industrial network that will be taken into account when identifying the risk should be determined. This is a factor depending on the initial network fragmentation, especially if the production plant has machines that use different software standards or different data transmission methods. The most frequently used techniques for identifying risks related to cybersecurity of industrial networks include:  
* Verification of machine documentation along with their communication and software standards. This method is aimed at verifying whether the communication standards used are protected against hacker attacks and whether the software of the machines is up-to-date and properly secured. In addition, a physical verification is performed whether all elements are compliant with the electrical documentation or they may have been replaced (e.g., during a breakdown) with a newer model offering up-to-date software. * Verification of the management of the architecture and network sections is aimed at checking whether all security standards defined during the creation of the network are maintained and properly managed by authorized persons. * Interviews with production plant employees responsible for the operation of machines and the security of the industrial network. Thanks to this method, it is possible to obtain information on security incidents or to obtain valuable information related to accidentally found errors in network configurations. * Verification of the management of special parts of the network and special devices active in the network. This applies to devices essential for the operation of the enterprise, which do not need to be directly and permanently connected to the industrial network. * The analysis of the configuration and settings in active network devices assumes the validation of the data entered into these devices. Additionally, this method checksthat the software offered by the manufacturer for the given devices is up to date in order to ensure a better level of security. * Monitoring the operation of devices responsible for security and verification of logs. This method consists of connecting devices operating in the 'Man in the Middle' mode, allowing the collection of an information packet without editing the data packet in order to track whether any of the devices intentionally modifies the signal or distorts it. Verification of device logs allows to see previous incidents related to the security of the industrial network. * Physical checking of security effectiveness during controlled attacks. This is probably the most effective method identified by security reports. It consists of carrying out a series of controlled attacks inside an industrial network in order to find its vulnerabilities and adequately protect against external exploitation of these vulnerabilities. * Port scan and network mapping to check robustness to network penetration. This method uses techniques related to the emulation of a given device in order to check the legitimacy and degree of authorization. * Analysis of the network diagrams, production process, policy and procedures. Such analysis can show how the users are using the industrial network and whether their cybersecurity knowledge corresponds to their rights in the network.