# A Review of Industry 4.0 Manufacturing Process Security Risks
## 3 Identifying the Problem
### The Problem in the Context of Industry 4.0
#### 3.4.1 The Manufacturing Information Architecture  
In previous sections the issue of intercepting manufacturing information between IT and OT platforms has been briefly introduced. In this section, we will zoom out on the problem statement in order to consider the flow of information between platforms in the digital manufacturing ecosystem as a whole. The case studies considered in Section 3.1 (which certainly do not represent an exhaustive selection) briefly introduced the nature of some cyber-physical attacks that have taken place in the past. Since these attacks have been aimed specifically at cyber-physical systems, and have been successful in their malicious intent, this paints a clear picture of what the scale of impact could be if similar attacks are performed on future smart manufacturing industries. It is also evident that the convergence between IT and OT platforms is a decisive factor in these types of attacks. Attackers can operate remotely from any location in the world via the Internet and subsequent digital networks, infiltrating vulnerable IT systems to carry out an attack on the underlying OT systems. Any malicious interception of information within the digital manufacturing ecosystem will mostly be aimed at obtaining and altering critical information on the product's manufacturing process. Apart from manufacturing process security, this also raises the issue of the protection of intellectual property [38]. Such critical information will be information that, if altered, could affect the product's functionality or structural integrity. Examples of such critical information include the bill of materials (BOM), the product design files and the manufacturing equipment control parameters. Each of these critical information items presents a unique attack vector that could be utilized for malicious intent. Consider as an example the 3D printing of a particular product within an industrial manufacturing environment. The filament specified in the product's BOM could be replaced with a filament that has a lower tensile strength, which would undoubtedly cause the end product to fail structurally if exposed to mechanical stress levels that cannot be withstood by the wrong filament. The effect of alterations to the CAD model design and manufacturing files has already been discussed in the previous section. Control parameters of the manufacturing equipment are also important in the product manufacturing process. For example, the temperature of the 3D printer's heat bed on which the product is printed is dependent on the type of filament used for the print. If the incorrect temperature setting is used with a specific filament, it could cause the foundation of the printed product to warp, and lead to an end product that is not dimensionally accurate compared to its design. Another example of such control parameters is the speed at which the 3D printer prints the product. If it is set higher than a specified standard (or according to the machine's specifications) it could cause the layer of filament to be too thin according to the design parameters. The printing speed could also be intermittently adjusted throughout the print, resulting in inconsistent layer thickness throughout the end product. Similarly, the speed of the head containing the spindle of a milling machine could be maliciously configured to a speed exceeding that specified by safe operating parameters, leading to damage to milling bits, causing unplanned downtime for maintenance. Along with the case studies considered in Section 3.1, the Maroochy Shire sewage spill considered in Section 2.1 is yet another typical example of how a cyber-physical system can be compromised, and to what extent it can have an impact beyond the environment of the cyber-physical system itself. As can be deduced from the examples presented in the previous paragraph, there are numerous possible scenarios of malicious interception that could each be detrimental to the final manufactured product.