ISA-IEC-62443 ISA/IEC 62443 Cybersecurity Fundamentals Specialist Free Practice Exam Questions (2026 Updated)

Even the most modern and sophisticated safety systems can be defeated by an attacker. This statement is validated by the discovery of malware specifically targeting safety instrumented systems (SIS), such as the "Triton/Trisis" malware that compromised the SIS of a petrochemical plant. Safety systems, while designed as independent protection layers, are not immune to cybersecurity vulnerabilities and require specific countermeasures. Integration, such as using Modbus TCP, does not inherently reduce risk to a tolerable level without additional controls.

 A cyber attack is an attempt to compromise the confidentiality, integrity, or availability of a computer system or network by exploiting its vulnerabilities. A cyber attack can be launched from various entry points, which are the pathways that allow an attacker to access a target system or network. According to the ISA/IEC 62443-3-2 standard, which defines a method for conducting a security risk assessment for industrial automation and control systems (IACS), some of the possible entry points for a cyber attack are:

LAN: A local area network (LAN) is a network that connects devices within a limited geographic area, such as a building or a campus. A LAN can be an entry point for a cyber attack if an attacker gains physical or logical access to the network devices, such as switches, routers, firewalls, or servers. An attacker can use various techniques to access a LAN, such as network scanning, spoofing, sniffing, or hijacking. An attacker can also exploit vulnerabilities in the network protocols, services, or applications that run on the LAN. A cyber attack on a LAN can affect the communication and operation of the devices and systems connected to the network, such as IACS.

Portable media: Portable media are removable storage devices that can be used to transfer data between different systems or devices, such as USB flash drives, CDs, DVDs, or external hard drives. Portable media can be an entry point for a cyber attack if an attacker uses them to introduce malicious code or data into a target system or device. An attacker can use various techniques to infect portable media, such as autorun, social engineering, or physical tampering. An attacker can also exploit vulnerabilities in the operating systems, drivers, or applications that interact with portable media. A cyber attack using portable media can affect the functionality and security of the systems or devices that use them, such as IACS.

Wireless: Wireless is a technology that enables communication and data transmission without physical wires or cables, such as Wi-Fi, Bluetooth, or cellular networks. Wireless can be an entry point for a cyber attack if an attacker intercepts, modifies, or disrupts the wireless signals or data. An attacker can use various techniques to access wireless networks or devices, such as cracking, jamming, or eavesdropping. An attacker can also exploit vulnerabilities in the wireless protocols, standards, or encryption methods. A cyber attack on wireless can affect the availability and reliability of the wireless communication and data transmission, such as IACS.

Therefore, LAN, portable media, and wireless are three possible entry points that could be used for launching a cyber attack. References:

Cybersecurity Risk Assessment According to ISA/IEC 62443-3-21

ISA/IEC 62443 Series of Standards2

The three general classes of firewalls are:

Packet Filtering Firewalls – Basic filters based on IPs, ports, protocols

Stateful Inspection Firewalls – Track active connections and session state

Application Proxy Firewalls – Act as intermediaries at the application layer

“Network inspection” is not a standard firewall classification, but rather a general term that may refer to DPI (Deep Packet Inspection) or NIDS (Network Intrusion Detection Systems).

“Firewall technologies are typically classified into packet filtering, stateful inspection, and application proxy types.”

— ISA/IEC 62443-3-3:2013, SR 5.1 – Zone Boundary Protection

ISA/IEC 62443-2-1 defines SP Element 4 as covering component hardening, malware protection, and the secure use of portable and mobile media. Malware introduced through USB devices is a well-known attack vector in IACS environments, and the standard addresses this risk explicitly through preventive controls rather than only reactive measures.

Step 1: Nature of the threat

Portable media such as USB drives bypass network-based defenses and can introduce malware directly into critical control systems. ISA/IEC 62443 recognizes this as a high-risk vector, especially in air-gapped or semi-isolated systems.

Step 2: SP Element 4 scope

SP Element 4 requires asset owners to implement technical controls such as:

Restrictions on the use of portable media

Use of dedicated, controlled media

Malware scanning before use

Hardening of endpoints to prevent unauthorized execution

Step 3: Why other SP Elements are secondary

SP Element 1 focuses on anomaly detection, not prevention.

SP Element 2 concerns inventory accuracy.

SP Element 7 applies after an incident has occurred.

Step 4: Preventive emphasis

The standard prioritizes prevention of malware introduction through controlled media usage, making SP Element 4 the most relevant.

Per ISA/IEC 62443-2-1 and 62443-2-3, proper patch management is part of operational cybersecurity. For high-priority or critical security patches, the best practice is to apply the patch at the earliest possible opportunity, often during the next available unscheduled or scheduled outage.

“Asset owners shall define procedures for evaluating and applying patches based on criticality and potential impact. High-priority patches should be applied at the earliest opportunity, preferably at the first available system downtime.”

— ISA/IEC 62443-2-3:2015, Clause 6.1 – Patch Management Process

Waiting unnecessarily or skipping patches because "nothing is broken" is not acceptable in security-critical environments.

In the ISA/IEC 62443 framework, Security Levels (SLs) are categorized into three distinct types:

Target SL (SL-T) – The security level required based on risk assessment

Capability SL (SL-C) – The level a component or system can support

Achieved SL (SL-A) – The level actually implemented in the system

“Three types of security levels are defined:

Target (SL-T): derived from risk analysis

Capability (SL-C): supported by the product or system

Achieved (SL-A): implemented and operational in the environment”

— ISA/IEC 62443-1-1:2007, Clause 3.2.4 and Table 3

This classification supports gap analysis and helps asset owners ensure their system meets both required and feasible security levels.

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