Free ISA ISA-IEC-62443 Practice Exam with Questions & Answers | Set: 2

 Safety management staff are stakeholders of the CSMS, which stands for Cybersecurity Management System. The CSMS is a framework for managing the cybersecurity of industrial automation and control systems (IACS) based on the ISA/IEC 62443-2-1 standard1. The CSMS defines the objectives, policies, metrics, and governance for the overall ICS security program2. The CSMS also includes the processes for risk assessment, security design, implementation, monitoring, and improvement3. Safety management staff are involved in the CSMS development and implementation, as they are responsible for ensuring the safety of the IACS and the people, environment, and assets that depend on it. Safety management staff need to coordinate with the security management staff to align the safety and security requirements, identify and mitigate the safety risks arising from cyber threats, and monitor and respond to safety incidents caused by cyberattacks. References:

• 1: ISA/IEC 62443-2-1: Establishing an Industrial Automation and Control Systems Security Program, ISA, 2010.
• 2: A Practical Approach to Adopting the IEC 62443 Standards - ISAGCA
• 3: ISA ISA-IEC-62443 ISA/IEC 62443 Cybersecurity Fundamentals Specialist Online Training - Exam4Training
• [4]: Using the ISA/IEC 62443 Standards to Secure Your Control System, ISA, 2018.

 Layer 2 of the OSI model is the data link layer, which is responsible for transferring data frames between nodes on a network segment. The data link layer is divided into two sublayers: logical link control (LLC) and media access control (MAC). The LLC sublayer deals with issues common to both dedicated and broadcast links, such as framing, flow control, and error control. The MAC sublayer deals with issues specific to broadcast links, such as how to access the shared medium and avoid collisions. The LLC and MAC sublayers are not related to the ISA/IEC 62443 cybersecurity standards, which focus on the security of industrial automation and control systems (IACS). References:https://www.baeldung.com/cs/data-link-sub-layers

https://bing.com/search?q=Layer+2+sublayers

 Intrusion detection systems (IDS) are tools that monitor network traffic and detect suspicious or malicious activity based on predefined rules or signatures. They are effective against known vulnerabilities, as they can alert the system administrators or security personnel when they encounter a match with a known attack pattern or behavior. However, IDS have some limitations and challenges, especially when applied to industrial automation and control systems (IACS). Some of these are:

• Modern IDS do not recognize IACS devices by default, as they are designed for general-purpose IT networks and protocols. Therefore, they may generate false positives or negatives when dealing with IACS-specific devices, protocols, or traffic patterns. To overcome this, IDS need to be customized or adapted to the IACS environment and context, which may require additional expertise and resources.
• They are not very inexpensive to design and deploy, as they require careful planning, configuration, testing, and maintenance. They also need to be integrated with other security tools and processes, such as firewalls, antivirus, patch management, incident response, etc. Moreover, they may introduce additional costs and risks, such as network performance degradation, data privacy issues, or legal liabilities.
• They are not effective against unknown or zero-day vulnerabilities, as they rely on predefined rules or signatures that may not cover all possible attack scenarios or techniques. Therefore, they may fail to detect novel or sophisticated attacks that exploit new or undiscovered vulnerabilities. To mitigate this, IDS need to be complemented with other security measures, such as anomaly detection, threat intelligence, or machine learning.
• They require a significant amount of care and feeding, as they need to be constantly updated, tuned, and monitored. They also generate a large amount of data and alerts, which may overwhelm the system administrators or security personnel. Therefore, they need to be supported by adequate tools and processes, such as data analysis, alert filtering, prioritization, correlation, or visualization.

References: ISA/IEC 62443-2-1:2010 - Establishing an industrial automation and control system security program, ISA/IEC 62443-3-3:2013 - System security requirements and security levels, ISA/IEC 62443 Cybersecurity Fundamentals Specialist Training Course, [Enhancing Modbus/TCP-Based Industrial Automation and Control Systems Security Using Intrusion Detection Systems]

Security Levels (SLs) are a way of expressing the security performance of an industrial automation and control system (IACS) or its components. SLs are broken down into three types: target, capability, and achieved1.

• Target SL is the level of security performance that is required for a system or component to protect against a specific threat scenario. The target SL is determined by conducting a risk assessment that considers the likelihood and impact of potential security incidents1.
• Capability SL is the level of security performance that a system or component can provide based on its design and implementation. The capability SL is determined by evaluating the security functions and features of the system or component against a set of security requirements1.
• Achieved SL is the level of security performance that a system or component actually provides in its operational environment. The achieved SL is determined by verifying that the system or component is properly installed, configured, maintained, and monitored1.

References: ISA/IEC 62443 Standards to Secure Your Industrial Control System, page 3-4.

 The risk analysis category of an IACS consists of two elements: business rationale and risk identification and classification1. Business rationale is the process of defining the scope, objectives, and criteria for the risk analysis, as well as the roles and responsibilities of the stakeholders involved. Risk identification and classification is the process of identifying the assets, threats, vulnerabilities, and consequences of a cyberattack on the IACS, and assigning a risk level to each scenario based on the likelihood and impact of the attack1. These elements are essential for establishing a baseline of the current risk posture of the IACS and determining the appropriate risk treatment measures to reduce the risk to an acceptable level. References: 1: ISA/IEC 62443-3-2:2020, Security for industrial automation and control systems - Part 3-2: Security risk assessment for system design, International Society of Automation, Research Triangle Park, NC, USA, 2020.

 According to the ISA/IEC 62443 Cybersecurity Fundamentals Specialist course, establishing policy, organization, and awareness is one of the four steps of the IACS cybersecurity lifecycle. This step involves defining the cybersecurity policies, roles, and responsibilities, as well as communicating them to the relevant stakeholders. It also involves establishing the risk tolerance level, which is the acceptable level of risk for the organization. Communicating policies and establishing the risk tolerance are both activities that are part of this step. Identifying detailed vulnerabilities and implementing countermeasures are activities that belong to the next steps of the lifecycle, which are assessing the current situation and implementing the cybersecurity program, respectively. References: ISA/IEC 62443 Cybersecurity Fundamentals Specialist course, Module 2: IACS Cybersecurity Lifecycle1

The reference model provides the overall conceptual basis in the design of an appropriate security program. It defines the common terminology, concepts, and models that can be used by all stakeholders responsible for IACS security. The reference model describes the general characteristics of IACS, the typical threats and vulnerabilities, the security lifecycle phases, and the security levels. The reference model also introduces the concepts of zones and conduits, which are used to group and isolate assets with similar security requirements and to control the communication between them. Referenceshttps://www.cisco.com/c/en/us/td/docs/solutions/Verticals/IoT_Security_Lab/IEC62443_WP.pdf

https://www.cisco.com/c/en/us/td/docs/solutions/Verticals/IoT_Security_Lab/IEC62443_WP.pdf

According to the ISA/IEC 62443-3-2 standard, implementing countermeasures is one of the steps in the security risk assessment for system design. The standard defines a comprehensive set of engineering measures to guide organizations through the process of assessing the risk of a particular industrial automation and control system (IACS) and identifying and applying security countermeasures to reduce that risk to tolerable levels. The standard recommends the following steps for implementing countermeasures:

• Establish the risk tolerance: This step involves determining the acceptable level of risk for the organization and the system under consideration, based on the business objectives, legal and regulatory requirements, and stakeholder expectations. The risk tolerance can be expressed as a target security level (SL-T) for each zone or conduit in the system.
• Select common countermeasures: This step involves selecting the appropriate security countermeasures for each zone or conduit, based on the SL-T and the existing security level (SL-A) of the system. The standard provides a list of common countermeasures for each security level, covering the domains of physical security, network security, system security, and application security. The selected countermeasures should be documented and justified in the security risk assessment report. References: ISA/IEC 62443 Cybersecurity Series Designated as IEC Horizontal Standards, Cybersecurity Risk Assessment According to ISA/IEC 62443-3-2

The primary responsibility of the network layer of the Open Systems Interconnection (OSI) model is to forward packets, including routing through intermediate routers. The network layer is the third layer from the bottom of the OSI model, and it is responsible for maintaining the quality of the data and passing and transmitting it from its source to its destination. The network layer also assigns logical addresses to devices, such as IP addresses, and uses various routing algorithms to determine the best path for the packets to travel. The network layer operates on packets, which are units of data that contain the source and destination addresses, as well as the payload. The network layer forwards packets from one node to another, using routers to switch packets between different networks. The network layer also handles host-to-host delivery, which means that it ensures that the packets reach the correct destination host.

The other choices are not correct because:

• B. Gives transparent transfer of data between end users. This is the responsibility of the transport layer, which is the fourth layer from the bottom of the OSI model. The transport layer provides reliable and error-free data transfer between end users, using protocols such as TCP and UDP. The transport layer operates on segments, which are units of data that contain the source and destination port numbers, as well as the payload. The transport layer also handles flow control, congestion control, and multiplexing.
• C. Provides the rules for framing, converting electrical signals to data. This is the responsibility of the data link layer, which is the second layer from the bottom of the OSI model. The data link layer provides the means for transferring data between adjacent nodes on a network, using protocols such as Ethernet and WiFi. The data link layer operates on frames, which are units of data that contain the source and destination MAC addresses, as well as the payload. The data link layer also handles error detection, error correction, and media access control.
• D. Handles the physics of getting a message from one device to another. This is the responsibility of the physical layer, which is the lowest layer of the OSI model. The physical layer provides the means for transmitting bits over a physical medium, such as copper wire, fiber optic cable, or radio waves. The physical layer operates on bits, which are the smallest units of data that can be either 0 or 1. The physical layer also handles modulation, demodulation, encoding, decoding, and synchronization.

References:

• The OSI Model – The 7 Layers of Networking Explained in Plain English1
• Network Layer in OSI Model2
• OSI model3

 The ISASecure conformance certification program is managed by the Security Compliance Institute (ISCI), a non-profit organization established in 2007 by a group of industry stakeholders, including end users, suppliers, and integrators. ISCI’s mission is to provide a common industry-accepted set of device and process requirements that drive device security, simplifying procurement for asset owners and device assurance for equipment vendors12. References: 1: ISASecure - IEC 62443 Conformance Certification - Official Site 2: Certifications - ISASecure