Authentic ISA Certification Exam ISA-IEC-62443 Questions Answers

A security policy refers to internal rules that govern how an organization protects critical system resources, such as industrial control systems (ICS). A security policy defines the objectives, scope, roles, responsibilities, and requirements for securing the ICS environment, as well as the procedures and guidelines for implementing, monitoring, and enforcing the security measures. A security policy also establishes the baseline for assessing and managing the security risks to the ICS, and for ensuring compliance with relevant standards, regulations, and best practices. A security policy is a key component of the ICS security program, and it should be documented, communicated, and reviewed regularly.

The other choices are not correct because:

• A. Formal guidance. Formal guidance refers to external sources of information and recommendations that can help an organization improve its ICS security posture, such as standards, frameworks, guidelines, and best practices. Formal guidance is not an internal rule, but rather a reference that can be used to develop, implement, and evaluate the security policy and controls. For example, the ISA/IEC 62443 series of standards provide formal guidance on how to secure ICS from cyber threats1.
• B. Legislation. Legislation refers to external laws and regulations that impose legal obligations and penalties on an organization for its ICS security performance, such as the NERC CIP standards for the electric sector2, or the EU NIS Directive for critical infrastructure operators3. Legislation is not an internal rule, but rather a compliance requirement that must be met by the organization. Legislation may also influence the security policy and controls, as the organization needs to align its security objectives and practices with the legal expectations and consequences.
• D. Code of conduct. A code of conduct refers to a set of ethical principles and values that guide the behavior and decision-making of an organization and its employees, such as honesty, integrity, respect, and accountability. A code of conduct is not an internal rule for protecting critical system resources, but rather a general norm for conducting business and maintaining a positive reputation. A code of conduct may also support the security policy and culture, as it can foster a sense of responsibility and trust among the ICS stakeholders.

References:

• 1: ISA/IEC 62443 Standards to Secure Your Industrial Control System
• 2: NERC Critical Infrastructure Protection Standards
• 3: EU Network and Information Systems Directive

Security zones are logical groupings of assets that share common security requirements based on factors such as criticality, consequence, vulnerability, and threat. Security zones are used to apply the principle of defense in depth, which means creating multiple layers of protection to prevent or mitigate cyberattacks. By creating security zones, asset owners can isolate the most critical or sensitive assets from the less critical or sensitive ones, and apply different levels of security controls to each zone according to the risk assessment. Security zones are not necessarily aligned with physical network segments, as assets within the same network may have different security requirements. For example, a network segment may contain both a safety instrumented system (SIS) and a human-machine interface (HMI), but the SIS has a higher security requirement than the HMI. Therefore, the SIS and the HMI should be in different security zones, even if they are in the same network segment. Similarly, assets within the same logical communication network may not have the same security requirements, and therefore should not be in the same security zone. For example, a logical communication network may span across multiple physical locations, such as a plant and a corporate office, but the assets in the plant may have higher security requirements than the assets in the office. Therefore, the assets in the plant and the office should be in different security zones, even if they are in the same logical communication network. Finally, all components in a large or complex system should not be in the same security zone, as this would create a single point of failure and expose the entire system to potential cyberattacks. Instead, the components should be divided into smaller and simpler security zones, based on their security requirements, and the communication between the zones should be controlled by conduits. Conduits are logical or physical connections between security zones that allow data flow and access control. Conduits should be designed to minimize the attack surface and the potential impact of cyberattacks, by applying security controls such as firewalls, encryption, authentication, and authorization. References:

• How to Define Zones and Conduits1
• Securing industrial networks: What is ISA/IEC 62443?2
• ISA/IEC 62443 Series of Standards3

According to the OSI model, the physical address is assigned in the layer 2, also known as the data link layer. The physical address is a unique identifier for each device on a network, such as a MAC address or a serial number. The data link layer is responsible for transferring data between adjacent nodes on a network, using the physical address to identify the source and destination of each frame. The data link layer also provides error detection and correction, flow control, and media access control. References: ISA/IEC 62443 Cybersecurity Fundamentals Specialist Exam Prep, section 2.2; ISA/IEC 62443 Standards to Secure Your Industrial Control System, section 3.1.2.