Free Practice Questions for ISA ISA-IEC-62443 Exam

 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

 IPSec is a commonly used protocol for managing secure data transmission over a VPN. IPSec stands for Internet Protocol Security and it is a set of standards that define how to encrypt and authenticate data packets that travel between two or more devices over an IP network. IPSec can operate in two modes: transport mode and tunnel mode. In transport mode, IPSec only encrypts the payload of the IP packet, leaving the header intact. In tunnel mode, IPSec encrypts the entire IP packet and encapsulates it in a new IP header. Tunnel mode is more secure and more suitable for VPNs, as it can protect the original source and destination addresses of the IP packet from eavesdropping or spoofing. IPSec uses two main protocols to provide security services: Authentication Header (AH) and Encapsulating Security Payload (ESP). AH provides data integrity and source authentication, but not confidentiality. ESP provides data integrity, source authentication, and confidentiality. IPSec also uses two protocols to establish and manage security associations (SAs), which are the parameters and keys used for encryption and authentication: Internet Key Exchange (IKE) and Internet Security Association and Key Management Protocol (ISAKMP). IKE is a protocol that negotiates and exchanges cryptographic keys between two devices. ISAKMP is a protocol that defines the format and structure of the messages used for key exchange and SA management.

One of the trends that has increased the security risks for industrial automation and control systems (IACS) is the integration of these systems with business and enterprise systems, such as enterprise resource planning (ERP), manufacturing execution systems (MES), and supervisory control and data acquisition (SCADA). This integration exposes the IACS to the same threats and vulnerabilities that affect the business and enterprise systems, such as malware, denial-of-service attacks, unauthorized access, and data theft. Moreover, the integration also creates new attack vectors and pathways for adversaries to compromise the IACS, such as through remote access, wireless networks, or third-party devices. Therefore, the integration of IACS with business and enterprise systems is a trend that has caused a significant percentage of security vulnerabilities. References: ISA/IEC 62443 Standards to Secure Your Industrial Control System, page 1-2.

A demilitarized zone (DMZ) in network architecture provides indirect (controlled and monitored) access to the Internet or untrusted networks, usually by isolating publicly accessible services (like web servers) from internal control networks. This prevents direct exposure of sensitive IACS assets to external threats. While DMZs can support secure data transfer, their primary function is segmentation and indirect access.

An intrusion detection system (IDS) is a network security tool that monitors network traffic and devices for known malicious activity, suspicious activity or security policy violations. The IDS sends alerts to IT and security teams when it detects any security risks and threats. However, an IDS does not block or prevent the malicious activity, it only detects and reports it. Therefore, an IDS is not the lock on the door for networks and computer systems, nor is it effective against all vulnerabilities in networks and computer systems. An IDS can be combined with an intrusion prevention system (IPS) to block the malicious activity in real time. References:

What is Intrusion Detection Systems (IDS)? How does it Work? | Fortinet1

Intrusion Detection System (IDS) - GeeksforGeeks2

What is an intrusion detection system (IDS)? - IBM3

In the NIST Cybersecurity Framework (CSF), “tiers” represent the degree to which an organization’s cybersecurity risk management practices exhibit the characteristics defined in the framework (such as risk awareness, repeatability, and adaptability). Tiers range from Partial (Tier 1) to Adaptive (Tier 4) and describe the organization's overall cybersecurity maturity or profile.

Tabletop exercises simulate cybersecurity incidents in a non-disruptive setting, helping teams test and improve their incident response plans and communication protocols.

“Tabletop exercises allow personnel to rehearse roles, responsibilities, and actions in a simulated event scenario. This enhances coordination, preparedness, and decision-making during actual incidents.”

— ISA/IEC 62443-2-1:2010, Clause 4.3.3.3 – Incident Response Preparedness

They are essential for verifying that the incident handling process (SP Element 7) is both understood and effective.

ISA/IEC 62443-3-2 focuses on the cybersecurity risk assessment process, including:

Identifying zones and conduits

Determining the Target Security Levels (SL-T)

Designing the IACS architecture based on risk-based zoning

“Part 3-2 defines a process for conducting cybersecurity risk assessments and designing system architectures that incorporate zones and conduits based on those risks.”

— ISA/IEC 62443-3-2:2020, Clause 5 – Risk Assessment Process

This part bridges the gap between risk evaluation and technical implementation.

The ISA/IEC 62443 standards series was originally developed by the International Society of Automation (ISA) and then adopted and published by the International Electrotechnical Commission (IEC) as the IEC 62443 series. The IEC is the primary international body responsible for the ongoing development, maintenance, and publication of these standards, which are recognized globally for IACS cybersecurity. ANSI is a US standards body, NIST is responsible for US federal cybersecurity frameworks, and ETSI develops telecommunications standards for Europe, but IEC is the correct answer here.

The primary goal of the NIST Cybersecurity Framework (CSF) is to help organizations enhance the security and resilience of critical infrastructure and reduce cybersecurity risks through a structured, risk-based approach.

“The Framework provides a policy framework of computer security guidance for how private sector organizations in the United States can assess and improve their ability to prevent, detect, and respond to cyber attacks. It is intended to enhance the resilience of critical infrastructure.”

— NIST CSF v1.1, Section 1.0 – Overview

The NIST CSF does not create new standards or certify organizations — it references existing standards and guides implementation in a flexible and sector-neutral way.