# Security Audit of a Blockchain-Based Industrial Application Platform
## 3 Attacker Goals, Resources, and Capabilities
### Types of Attacks  
In this section, attacks applicable to the described BISS:4.0 platform were investigated, categorized, described, and classified. While a variety of attacks exist on software and hardware, the following only discusses attacks that target the category of cyber-physical systems in the industrial environment [1]. The retrofitting of sensors in existing machines results in additional attack vectors from the category of IoT. As shown in Figure 3, attacks can be divided into five main categories: (1) data attacks, (2) communication channel attacks, (3) role attacks, (4) encryption attacks, and (5) infrastructure attacks (The attack categorization was partly inspired by [32], but IoT-specific parts were omitted and other parts were added or modified to fit the use case.). Attacks in the role category grant unauthorized access and can be prevented by using TLS encryption and authentication for general communication. Registering the identity of users in the blockchain prevents the following attacks: social engineering, phishing, spoofing credentials, and certificate and spoofed node. In the mobile application area, only password attacks can occur in user identification and spoofing in device identification.  
The communication channel category includes attacks that manipulate or eavesdrop on traffic in the network part of the architecture. Most of these attacks can be mitigated by encrypting the traffic (by using TLS or a VPN). Active attacks such as DNS spoofing, handshake attacks, and signal manipulation are also difficult to perform when communicating only over encrypted channels. It can even be beneficial to combine these two solutions, for example, by tunneling all TLS traffic through an enterprise VPN. In the case of subsequent vulnerabilities in TLS itself (e.g., POODLE [33] and subsequently [34], which affected all TLS versions except TLS 1.2 with AEAD cipher suites) or in the case of a particular TLS implementation (e.g., Heartbleed [35]), there is an additional securely encrypted layer that guarantees that no data is exposed. There are several types of attacks that target the data flowing through the system: data exposure, data scavenging, and data tampering attacks are not effective because the system uses encrypted transport protocols, stores hashed data, and uses smart contracts to validate the data. In the category of encryption attacks, the risk of unknown vulnerabilities in cryptographic algorithms must be distinguished from attacks on a specific implementation, but both risks can be minimized by using known and widely used algorithms and implementations. Side channel attacks (e.g., meltdown) can be mitigated by upgrading the operating system or hardware. Attacks on infrastructure are divided into attacks on hardware and software. However, hardware attacks such as physical damage, social engineering, object replication attack, node manipulation, hardware Trojan, malicious code injection, node disruption, and sleep deprivation attacks on the proposed system are questionable because they require physical access to the system. It can be assumed that unauthorized physical access to the system is prevented by access controls. Software attacks such as phishing, malware, and spyware, on the other hand, can be carried out from a remote location.