Pass the ISA Cybersecurity ISA-IEC-62443 Questions and answers with CertsForce

Authorization is the process of granting or denying access to a network resource or function. Authorization (user accounts) must be granted based on specific roles, which are defined as sets of permissions and responsibilities assigned to a user or a group of users. Roles should be based on the principle of least privilege, which means that users should only have the minimum level of access required to perform their tasks. Roles should also be based on the principle of separation of duties, which means that users should not have conflicting or overlapping responsibilities that could compromise the security or integrity of the system. Authorization based on individual preferences or common needs for large groups is not recommended, as it could lead to excessive or unnecessary access rights, or to inconsistent or conflicting policies. Authorization based on system complexity is also not a good criterion, as it could result in overcomplicated or unclear roles that are difficult to manage or audit. References:

ISA/IEC 62443-3-3:2013 - Security for industrial automation and control systems - Part 3-3: System security requirements and security levels1

ISA/IEC 62443-2-1:2010 - Security for industrial automation and control systems - Part 2-1: Establishing an industrial automation and control systems security program2

ISA/IEC 62443-4-1:2018 - Security for industrial automation and control systems - Part 4-1: Product security development life-cycle requirements3

ISA/IEC 62443 clearly assigns operational cybersecurity responsibility to the asset owner. During the Operate and Maintain phase of the IACS lifecycle, the asset owner is accountable for ensuring that cybersecurity controls are executed, monitored, and adapted as risks evolve.

Step 1: Definition of the SPS

IEC 62443-2-2 defines the Security Protection Scheme (SPS) as a documented set of technical, procedural, and physical measures selected to manage cybersecurity risk. While other parties may contribute to its design or implementation, execution during operation is the asset owner’s responsibility.

Step 2: Operational accountability

ISA/IEC 62443-2-1 establishes that the asset owner must operate and maintain the IACS security program, including incident handling, vulnerability management, patching, monitoring, and response to emerging threats.

Step 3: Why other roles are incorrect

Product vendors are responsible for product security, not operational risk response.

System integrators support design and implementation, not ongoing ownership.

External auditors assess compliance but do not execute controls.

Step 4: Risk ownership principle

Because the asset owner bears the consequences of downtime, safety incidents, and regulatory impact, the standard assigns them responsibility for executing SPS measures and responding to new risks.

Therefore, Option A is correct.

The SL-T (BPCS Zone) vector {2 2 0 1 3 1 3} represents the Target Security Level (SL-T) across each of the seven Foundational Requirements (FRs) in ISA/IEC 62443-3-3.

Each number in the vector corresponds to a security level (0–4) assigned to a particular FR, as follows:

FR1 – Identification & Authentication Control (IAC): 2

FR2 – Use Control (UC): 2

FR3 – System Integrity (SI): 0

FR4 – Data Confidentiality (DC): 1

FR5 – Restricted Data Flow (RDF): 3

FR6 – Timely Response to Events (TRE): 1

FR7 – Resource Availability (RA): 3

“Security levels are represented as vectors of seven values, each corresponding to the target security level for a foundational requirement (FR).”

— ISA/IEC 62443-3-3:2013, Annex A – SL Vector Format

This allows zone-specific tailoring based on risk — some FRs may require SL 3, others SL 0, depending on system criticality and exposure.

According to ISA/IEC 62443-3-2, the risk analysis phase in the IACS security lifecycle includes both the business rationale and the risk identification and classification. This ensures that risk decisions are based not only on technical vulnerability but also on business impact and operational context.

“The risk analysis process includes identification and classification of risks based on a defined business rationale. This ensures that the protection requirements are aligned with the organization’s risk tolerance and operational priorities.”

— ISA/IEC 62443-3-2:2020, Section 6.4 – Risk Assessment and SL Targeting

The term business rationale refers to understanding the value and criticality of the asset or system in order to make informed security decisions.

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.

The Triton (also known as Trisis) malware specifically targeted and compromised Safety Instrumented Systems (SIS), disabling the emergency shutdown capabilities at a petrochemical plant. This attack demonstrated that safety systems, once considered isolated and secure, are vulnerable to sophisticated, targeted cyberattacks. Neither Zeus, Stuxnet, nor WannaCry had this specific impact on emergency shutdown safety systems.

The ISA/IEC 62443 standards are divided into four main groups: General, Policies and Procedures, System, and Component. The first group, “General,” includes foundational standards and technical reports that provide essential concepts, models, terminology, and overall guidance for the rest of the series. This includes parts such as 62443-1-1 (concepts and models), 1-2 (glossary), 1-3 (metrics), and 1-4 (security lifecycle and use cases).

A Process Hazard Analysis (PHA) is a systematic method of identifying and evaluating the potential hazards associated with an industrial process. A PHA can help to identify the sources of cyber threats, the consequences of cyber incidents, and the existing safeguards and mitigation measures. A PHA is most frequently used as an input to a security risk assessment because it provides a comprehensive and structured overview of the process and its risks, which can then be used to determine the security level targets and security countermeasures for the industrial automation and control system (IACS). A PHA can also help to align the security objectives with the safety objectives of the process, and to ensure that the security measures do not compromise the safety or operability of the process. References:

ISA/IEC 62443 Standards to Secure Your Industrial Control System, page 10

Using the ISA/IEC 62443 Standard to Secure Your Control System, page 17

 Layer 1 of the ISO/OSI protocol stack is the physical layer, which provides the means of transmitting and receiving raw data bits over a physical medium. It defines the electrical and physical specifications of the data connection, such as the voltage levels, signal timing, cable types, connectors, and pin assignments. It does not perform any data encryption, routing, end-to-end connectivity, framing, error checking, or user applications. These functions are performed by higher layers of the protocol stack, such as the data link layer, the network layer, the transport layer, and the application layer. References: ISO/IEC 7498-1:1994, Section 6.11; ISA/IEC 62443 Cybersecurity Fundamentals Specialist Study Guide, Section 3.1.12

ISO/IEC 27001 is the international standard that defines requirements for establishing, implementing, maintaining, and continually improving an Information Security Management System (ISMS) across an organization.

Step 1: Scope of ISO/IEC 27001

ISO/IEC 27001 applies broadly to all information assets, including IT systems, business processes, and organizational data, regardless of industry.

Step 2: Contrast with ISA/IEC 62443

ISA/IEC 62443 focuses specifically on Industrial Automation and Control Systems, addressing OT-specific risks such as safety, availability, and real-time constraints. While 62443-2-1 aligns with ISMS principles, it is not a general-purpose ISMS standard.

Step 3: Complementary use

Organizations commonly use ISO/IEC 27001 for enterprise-wide information security and ISA/IEC 62443 for OT/IACS environments.

Thus, the standard focused on protecting sensitive information across all organizational systems via an ISMS is ISO/IEC 27001.