ISA ISA-IEC-62443 Questions Answers

 The ISA/IEC 62443 standards are focused on industrial automation and control systems security. The assess phase within the ISA/IEC 62443 framework is designed to identify and analyze potential vulnerabilities in the industrial control system (ICS) environment. One of the key steps in this phase is the specification of cybersecurity requirements. Additionally, it involves the allocation of industrial automation and control system (IACS) assets to defined zones and conduits to manage and segregate the network and improve security. These measures help to ensure that security requirements are met and that the assets are protected according to their security needs. Therefore, the correct answer is B, which mentions both the cybersecurity requirements specification and the allocation of IACS assets to zones and conduits as part of the assess phase.

Role-based access control (RBAC) is a method of restricting access to resources based on the roles of individual users within an organization. RBAC assigns permissions and responsibilities to roles, rather than to individual users, and then assigns users to those roles. This way, users can only perform the actions that are relevant and necessary for their role, and not access or modify any other resources that are beyond their scope of authority. RBAC is one of the security countermeasures that can be implemented in a defense-in-depth strategy, which is a layered approach to protect industrial automation and control systems (IACS) from cyber threats. RBAC can help prevent unauthorized access, misuse, or sabotage of IACS resources, as well as reduce the risk of human error or insider attacks.

References:

• ISA/IEC 62443-3-3:2013, Security for industrial automation and control systems - Part 3-3: System security requirements and security levels, Clause 5.3.2.11
• ISA/IEC 62443-2-1:2010, Security for industrial automation and control systems - Part 2-1: Establishing an industrial automation and control systems security program, Clause 6.2.2.32
• ISA/IEC 62443-4-1:2018, Security for industrial automation and control systems - Part 4-1: Product security development life-cycle requirements, Clause 5.2.3.23
• ISA/IEC 62443-4-2:2019, Security for industrial automation and control systems - Part 4-2: Technical security requirements for IACS components, Clause 4.2.3.24

 OPC Classic uses DCOM, which dynamically assigns any port between 1024 and 65535. Comprehensive Explanation: OPC Classic is a software interface technology that uses the Distributed Component Object Model (DCOM) protocol to facilitate the transfer of data between different industrial control systems. DCOM is a Microsoft technology that allows applications to communicate across a network. However, DCOM is not designed with security in mind, and it poses several challenges for firewall configuration. One of the main challenges is that DCOM does not use fixed TCP port numbers, but rather negotiates new port numbers within the first open connection. This means that intermediary firewalls can only be used with wide-open rules, leaving a large range of ports open for potential attacks. This makes OPC Classic very “firewall unfriendly” and reduces the security and protection they provide. References:

• Tofino Security OPC Foundation White Paper
• Step 2 (for client or server): Configuring firewall settings - GE
• Secure firewall for OPC Classic - Design World

According to the ISA/IEC 62443-3-2 standard, a security zone is a grouping of systems and components based on their functional, logical, and physical relationship that share common security requirements. The primary objective of defining a security zone is to apply a consistent level of protection to the assets within the zone, based on their criticality and risk assessment. A security zone may contain assets from different vendors, different levels in the Purdue model, or different physical locations, as long as they have the same security requirements. A security zone may also be subdivided into subzones, if there are different security requirements within the zone. A conduit is a logical or physical grouping of communication channels connecting two or more zones that share common security requirements.

References:

• ISA/IEC 62443-3-2:2020, Security for industrial automation and control systems - Part 3-2: Security risk assessment for system design, Clause 4.3.21
• ISA/IEC 62443-1-1:2009, Security for industrial automation and control systems - Part 1-1: Terminology, concepts and models, Clause 3.2.42