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

The ISA/IEC 62443 series of standards is divided into four main parts, each covering a different aspect of industrial automation and control systems (IACS) cybersecurity1:

Part 1: Terminology, Concepts, and Models

Part 2: Policies and Procedures

Part 3: System Requirements

Part 4: Component Requirements The part 4 of the series focuses on the requirements for the secure development and maintenance of products that are used in IACS, such as controllers, sensors, actuators, network devices, software applications, and cloud services. The part 4 consists of two standards1:

ISA/IEC 62443 defines Security Levels (SL 0–4) as qualitative representations of the system’s ability to withstand different attacker capabilities. These definitions are consistent across system (3-3) and component (4-2) requirements.

Step 1: Understanding attacker models

SL 1 addresses casual or accidental misuse.

SL 2 addresses intentional violations using simple means and low skill.

SL 3 addresses intentional violations using sophisticated means with moderate skills.

SL 4 addresses highly sophisticated attackers with extended resources.

Step 2: Match requirement to definition

The question explicitly describes:

Intentional violations

Sophisticated means

Moderate skill level

This description directly aligns with the formal definition of SL 3.

Step 3: Why other SLs do not fit

SL 1 and SL 2 do not account for sophisticated attack techniques.

SL 4 assumes nation-state–level capability and extensive resources, which exceeds the stated threat.

Step 4: Risk-based targeting

ISA/IEC 62443-3-2 requires asset owners to select a Target Security Level (SL-T) based on risk assessment. When threats involve deliberate, technically capable attackers but not extreme resources, SL 3 is the appropriate target.

Therefore, the correct and standards-aligned answer is SL 3.

The ISASecure certification program, aligned with the ISA/IEC 62443 standards, defines three distinct security levels that categorize the robustness of industrial control systems against known cybersecurity threats. These levels are designed to provide a scalable approach to securing industrial automation and control systems, with each level offering a higher degree of security. The levels are typically identified as SL1 (Security Level 1), SL2 (Security Level 2), and SL3 (Security Level 3), each addressing increasingly stringent security capabilities and resilience against cyber attacks.

Documenting the results of the initial or high-level risk assessment is crucial to establish a baseline for cybersecurity posture and risk. This baseline serves as a reference for tracking progress, justifying future investments, measuring improvements, and supporting subsequent detailed risk assessments. It also aids in communication with stakeholders and auditors.