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

A Wide Area Network (WAN) is a communications system that covers a large geographic area, such as a city, a country, or even several countries or continents1. WANs are often used to connect local area networks (LANs) and other types of networks together, so that users and computers in one location can communicate with users and computers in other locations2. WANs use various communication infrastructures, such as public telephone lines, undersea cables, and communication satellites, to transmit data over long distances1. WANs are typically established with leased telecommunication circuits or less costly circuit switching or packet switching methods2. WANs are often built by Internet service providers, who provide connections from an organization’s LAN to the Internet2. The Internet itself may be considered a WAN2. References: Hardware and network technologies - CCEA LAN and WAN - BBC, Wide area network - Wikipedia.

 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.

References:

• ISA/IEC 62443-3-3:2018, Section 4.2.3.7.1, VPN1
• ISA/IEC 62443-4-2:2019, Section 4.2.3.7.1, VPN
• ISA/IEC 62443 Cybersecurity Fundamentals Specialist Study Guide, Section 5.3.2, VPN
• ISA/IEC 62443 Cybersecurity Fundamentals Specialist Exam Specification, Section 5.3.2, VPN

The selection of countermeasures is driven by the output from a risk assessment, which identifies the risks and their associated likelihood and consequences for each zone and conduit in the industrial automation and control system (IACS). The risk assessment also determines the target security level (SL-T) for each zone and conduit, which represents the desired level of protection against the identified threats. The countermeasures are then selected based on the SL-T and the existing security level (SL-A) of the zone and conduit, as well as the cost and feasibility of implementation. The countermeasures should aim to reduce the risk to an acceptable level by increasing the SL-A to meet or exceed the SL-T. References: ISA/IEC 62443-3-2:2018 - Security risk assessment for system design, ISA/IEC 62443-3-3:2013 - System security requirements and security levels, ISA/IEC 62443 Cybersecurity Fundamentals Specialist Training Course

 Periodic audits are an essential part of the ISA/IEC 62443 cybersecurity standards, as they help to verify the effectiveness and compliance of the security program. According to the ISA/IEC 62443-2-1 standard, periodic audits should be conducted to evaluate the following aspects1:

• The security policies and procedures are consistent with the security requirements and objectives of the organization
• The security policies and procedures are implemented and enforced in accordance with the security program
• The security policies and procedures are reviewed and updated regularly to reflect changes in the threat landscape, the IACS environment, and the business needs
• The security performance indicators and metrics are measured and reported to the relevant stakeholders
• The security incidents and vulnerabilities are identified, analyzed, and resolved in a timely manner
• The security awareness and training programs are effective and aligned with the security roles and responsibilities of the personnel
• The security audits and assessments are conducted by qualified and independent auditors
• The security audit and assessment results are documented and communicated to the appropriate parties
• The security audit and assessment findings and recommendations are addressed and implemented in a prioritized and systematic way Periodic audits are not only a means to meet regulations or adhere to a schedule, but also a way to validate that the security policies and procedures are performing as intended and achieving the desired security outcomes. Periodic audits also help to identify gaps and weaknesses in the security program and provide opportunities for improvement and enhancement. References: Periodic audits are an essential part of the ISA/IEC 62443 cybersecurity standards, as they help to verify the effectiveness and compliance of the security program. According to the ISA/IEC 62443-2-1 standard, periodic audits should be conducted to evaluate the following aspects1:
• The security policies and procedures are consistent with the security requirements and objectives of the organization
• The security policies and procedures are implemented and enforced in accordance with the security program
• The security policies and procedures are reviewed and updated regularly to reflect changes in the threat landscape, the IACS environment, and the business needs
• The security performance indicators and metrics are measured and reported to the relevant stakeholders
• The security incidents and vulnerabilities are identified, analyzed, and resolved in a timely manner
• The security awareness and training programs are effective and aligned with the security roles and responsibilities of the personnel
• The security audits and assessments are conducted by qualified and independent auditors
• The security audit and assessment results are documented and communicated to the appropriate parties
• The security audit and assessment findings and recommendations are addressed and implemented in a prioritized and systematic way Periodic audits are not only a means to meet regulations or adhere to a schedule, but also a way to validate that the security policies and procedures are performing as intended and achieving the desired security outcomes. Periodic audits also help to identify gaps and weaknesses in the security program and provide opportunities for improvement and enhancement. References: