ISA Updated ISA-IEC-62443 Exam Questions and Answers by fleur

According to ISA/IEC 62443-2-4, which defines security requirements for IACS service providers, four maturity levels (ML1–ML4) are established as evaluation criteria for measuring the maturity of cybersecurity practices.

These are:

ML1 – Initial

ML2 – Managed

ML3 – Defined

ML4 – Improving

“This standard defines four maturity levels (ML1 through ML4) to assess the extent of cybersecurity process implementation for service providers.”

— ISA/IEC 62443-2-4:2015, Clause 5.1 – Maturity Level Overview

These maturity levels are used to benchmark and certify service provider practices across different domains like patching, access control, and incident response.

The second edition (2024) of ISA/IEC 62443-2-1 introduced a significant structural improvement by eliminating duplication of Information Security Management System (ISMS) requirements. The first edition (2010) contained content that overlapped substantially with ISO/IEC 27001-style ISMS controls, leading to redundancy and unnecessary implementation burden.

In the updated edition, ISA clarified that 62443-2-1 is not intended to replace a general-purpose ISMS, but rather to extend and specialize it for Industrial Automation and Control Systems (IACS). As a result, duplicated ISMS clauses were removed or streamlined, and the focus shifted to IACS-specific risks, operational realities, and lifecycle concerns.

This change improves:

Compatibility with existing enterprise ISMS implementations

Clarity of roles between IT security governance and OT security management

Practical adoption by asset owners operating both IT and OT environments

Importantly, supply chain security, lifecycle management, and organizational governance were not removed. Instead, they were better aligned and referenced to avoid redundancy. The PDCA model remains implicit but was not newly introduced in 2024.

Thus, the defining change is the elimination of duplicated ISMS requirements, making Option B correct.

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

Secure Sockets Layer (SSL) is no longer considered secure due to known vulnerabilities and cryptographic weaknesses. Modern standards require the use of newer versions of Transport Layer Security (TLS), and similarly, DES is deprecated for strong security. However, the best and most universally referenced example is SSL, as major industry and regulatory bodies recommend disabling SSL entirely in favor of TLS 1.2 or above.