OPC Classic uses DCOM, which dynamically assigns any port between 1024 and 65535. Comprehensive Explanation: OPC Classic is a software interface technology that uses the Distributed Component Object Model (DCOM) protocol to facilitate the transfer of data between different industrial control systems. DCOM is a Microsoft technology that allows applications to communicate across a network. However, DCOM is not designed with security in mind, and it poses several challenges for firewall configuration. One of the main challenges is that DCOM does not use fixed TCP port numbers, but rather negotiates new port numbers within the first open connection. This means that intermediary firewalls can only be used with wide-open rules, leaving a large range of ports open for potential attacks. This makes OPC Classic very “firewall unfriendly” and reduces the security and protection they provide. References:

• Tofino Security OPC Foundation White Paper
• Step 2 (for client or server): Configuring firewall settings - GE
• Secure firewall for OPC Classic - Design World

Multiuser accounts and shared passwords are accounts and passwords that are used by more than one person to access a system or a resource. They inherently carry the risk of unauthorized access, which means that someone who is not authorized or intended to use the account or password can gain access to the system or resource, and potentially compromise its confidentiality, integrity, or availability. For example, if a multiuser account and password are shared among several operators of an industrial automation and control system (IACS), an attacker who obtains the password can use the account to access the IACS and perform malicious actions, such as changing the system settings, deleting data, or disrupting the process. Multiuser accounts and shared passwords also make it difficult to track and audit the activities of individual users, and to enforce the principle of least privilege, which states that users should only have the minimum level of access required to perform their tasks. Therefore, the ISA/IEC 62443 standards recommend avoiding the use of multiuser accounts and shared passwords, and instead using individual accounts and strong passwords for each user, and implementing authentication and authorization mechanisms to control the access to the IACS. References:

• ISA/IEC 62443-3-3:2013 - Security for industrial automation and control systems - Part 3-3: System security requirements and security levels1
• ISA/IEC 62443-2-1:2009 - Security for industrial automation and control systems - Part 2-1: Establishing an industrial automation and control systems security program2
• ISA/IEC 62443 Cybersecurity Fundamentals Specialist Training Course3

Shared passwords and multiuser accounts pose specific risks, notably unauthorized access and privilege escalation. In ISA/IEC 62443's framework, these practices are discouraged because they complicate the attribution of actions to individual users and increase the likelihood that accounts can be used beyond their intended scope. Unauthorized access occurs when individuals exploit the shared nature of an account to gain entry to systems or data that they should not access. Privilege escalation can happen when users leverage shared accounts to perform actions at higher permission levels than those assigned to their personal accounts. Conversely, buffer overflows and race conditions are types of vulnerabilities or programming errors, not directly associated with the risks of multiuser accounts or shared passwords.

A Process Hazard Analysis (PHA) is a systematic and structured method of identifying and evaluating the potential hazards and risks associated with an industrial process. A PHA can help to identify the possible causes and consequences of undesired events, such as equipment failures, human errors, cyberattacks, natural disasters, etc. A PHA can also provide recommendations for reducing the likelihood and severity of such events, as well as improving the safety and security of the process. A PHA is one of the most frequently used analysis methods as an input to a security risk assessment, as it can help to identify the assets, threats, vulnerabilities, and impacts related to the process, and provide a basis for determining the security risk level and the appropriate security countermeasures. A PHA is also a requirement of the ISA/IEC 62443 standard, as part of the security program development and implementation phase12. References: 1: ISA/IEC 62443-2-1: Security for industrial automation and control systems: Establishing an industrial automation and control systems security program 2: ISA/IEC 62443-3-2: Security for industrial automation and control systems: Security risk assessment for system design

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

One of the reasons for the increase in attacks on IACS is the availability of information and tools that can be used to exploit vulnerabilities in these systems. The Internet provides a platform for hackers, researchers, and activists to share their knowledge and techniques for compromising IACS. Some examples of such information and tools are:

• Stuxnet: A sophisticated malware that targeted the Iranian nuclear program in 2010. It exploited four zero-day vulnerabilities in Windows and Siemens software to infect and manipulate the programmable logic controllers (PLCs) that controlled the centrifuges. Stuxnet was widely analyzed and reported by the media and security experts, and its source code was leaked online1.
• Metasploit: A popular penetration testing framework that contains modules for exploiting various IACS components and protocols. For instance, Metasploit includes modules for attacking Modbus, DNP3, OPC, and Siemens S7 devices2.
• Shodan: A search engine that allows users to find devices connected to the Internet, such as webcams, routers, printers, and IACS components. Shodan can reveal the location, model, firmware, and configuration of these devices, which can be used by attackers to identify potential targets and vulnerabilities3.
• ICS-CERT: A website that provides alerts, advisories, and reports on IACS security issues and incidents. ICS-CERT also publishes vulnerability notes and mitigation recommendations for various IACS products and vendors4. These sources of information and tools can be useful for legitimate purposes, such as security testing, research, and education, but they can also be misused by malicious actors who want to disrupt, damage, or steal from IACS. Therefore, IACS owners and operators should be aware of the threats and risks posed by the Internet and implement appropriate security measures to protect their systems. References:
• The increase in attacks on Industrial Automation and Control Systems (IACS) can be attributed to several factors, including: A.Use of proprietary communications protocols:These can pose security risks because they may not have been designed with security in mind and are often not as well-tested against security threats as more standard protocols. C.Knowledge of exploits and tools readily available on the Internet:The availability of information about vulnerabilities and exploits on the internet has made it easier for attackers to target IACS.
• The other options, B and D, are incorrect because: B. The move towards commercial off-the-shelf (COTS) systems, protocols, and networks actually increases risk because these systems are more likely to be known and targeted by attackers, compared to proprietary systems which might benefit from security through obscurity. D. There is actually an increase in risk with more personnel with system knowledge because it enlarges the attack surface – each individual with system knowledge can potentially become a vector for an attack, either maliciously or accidentally.

According to the ISA/IEC 62443 Cybersecurity Fundamentals, the risk matrix is a tool used to assess the risk of a particular event. The risk matrix is divided into three categories: likelihood, consequence, and risk. The likelihood is the probability that an event will occur, the consequence is the impact that the event will have, and the risk is the combination of the two. In this case, the risk of a medium likelihood event with high consequence is a high risk, as shown by the red cell in the matrix. References:

• ISA/IEC 62443 Cybersecurity Fundamentals
• [ISA/IEC 62443 Cybersecurity Certificate Program]
• [Cybersecurity Library]
• [Using the ISA/IEC 62443 Standard to Secure Your Control Systems]

The ISASecure Integrated Threat Analysis (ITA) Program is a certification scheme that certifies off-the-shelf automation and control systems to the ISA/IEC 62443 series of standards1. The ITA Program consists of three main components2:

• Software Development Security Assurance (SDSA): This component evaluates the security lifecycle and practices of the product supplier, such as security requirements, design, implementation, verification, and maintenance. The SDSA certification is based on the ISA/IEC 62443-4-1 standard.
• Functional Security Assessment (FSA): This component verifies the security functions and features implemented in the product, such as identification and authentication, access control, encryption, audit logging, and security management. The FSA certification is based on the ISA/IEC 62443-4-2 standard.
• Communications Robustness Testing (CRT): This component tests the resilience of the product against network attacks, such as denial-of-service, fuzzing, spoofing, and replay. The CRT certification is based on the ISA/IEC 62443-4-2 and ISA/IEC 62443-3-3 standards .

References:

• 1: ISASecure - IEC 62443 Conformance Certification - Official Site
• 2: ISASecure - IEC 62443 Conformance Certification - Official Site
• [3]: ISA/IEC 62443-4-1: Secure Product Development Lifecycle Requirements, ISA, 2018.
• [4]: ISA/IEC 62443-4-2: Technical Security Requirements for IACS Components, ISA, 2019.
• [5]: ISA/IEC 62443-4-2: Technical Security Requirements for IACS Components, ISA, 2019.
• [6]: ISA/IEC 62443-3-3: System Security Requirements and Security Levels, ISA, 2013.

The “Addressing Risk” CSMS category consists of three element groups: Security Policy, Organization and Awareness; Selected Security Countermeasures; and Implementation of Security Program1. These element groups cover the aspects of defining the security objectives, roles and responsibilities, policies and procedures, awareness and training, security countermeasures selection and implementation, and security program execution and maintenance1. The “Addressing Risk” CSMS category aims to reduce the security risk to an acceptable level by applying appropriate security measures to the system under consideration (SuC)1. References: 1: ISA/IEC 62443-2-1: Security for industrial automation and control systems: Establishing an industrial automation and control systems security program

 ISA-TR62443-2-3 is the technical report that describes the requirements for asset owners and industrial automation and control system (IACS) product suppliers that have established and are now maintaining an IACS patch management program. Patch management is the process of applying software updates to fix vulnerabilities, bugs, or performance issues in the IACS components. Patch management is an essential part of maintaining the security and reliability of the IACS environment. The technical report provides guidance on how to establish a patch management policy, how to assess the impact and risk of patches, how to test and deploy patches, and how to monitor and audit the patch management process. References: 1, 2, 3

Patches are software updates that fix bugs, vulnerabilities, or improve performance or functionality. Patches are important for maintaining the security and reliability of an IACS environment, but they also pose some challenges and risks. Applying patches in an IACS environment is not as simple as in an IT environment, because patches may affect the availability, integrity, or safety of the IACS. Therefore, patches should not be applied blindly or automatically, but based on the organization’s risk assessment. The risk assessment should consider the following factors: 1

• The severity and likelihood of the vulnerability that the patch addresses
• The impact of the patch on the IACS functionality and performance
• The compatibility of the patch with the IACS components and configuration
• The availability of a backup or recovery plan in case the patch fails or causes problems
• The testing and validation of the patch before applying it to the production system
• The communication and coordination with the stakeholders involved in the patching process
• The documentation and auditing of the patching activities and results References: ISA TR62443-2-3 - Security for industrial automation and control systems, Part 2-3: Patch management in the IACS environment

API 1164 is an industry sector-specific standard that provides guidance on the cybersecurity of pipeline supervisory control and data acquisition (SCADA) systems. API stands for American Petroleum Institute, which is the largest U.S. trade association for the oil and natural gas industry. API 1164 was first published in 2004 and revised in 2009 and 2021. The latest version of the standard aligns with the ISA/IEC 62443 series of standards and incorporates the concepts of security levels, zones, and conduits. API 1164 covers the security lifecycle of pipeline SCADA systems, from risk assessment and policy development to implementation and maintenance. The standard also defines roles and responsibilities, security requirements, security controls, and security assessment methods for pipeline SCADA systems.

References:

• API 1164: Pipeline SCADA Security, Fourth Edition, September 2021
• ISA/IEC 62443 Cybersecurity Fundamentals Specialist Study Guide, Section 2.2.2, Industry Sector-Specific Standards
• ISA/IEC 62443 Cybersecurity Fundamentals Specialist Exam Specification, Section 2.2.2, Industry Sector-Specific Standards

According to the ISA/IEC 62443-1-1 standard, an industrial automation and control system (IACS) is defined as a collection of personnel, hardware, and software that can affect or influence the safe, secure, and reliable operation of an industrial process. The hardware and software components of an IACS include the control system, which is the combination of control devices, networks, and applications that perform the control functions for the industrial process. The control system may consist of various types of devices, such as distributed control systems (DCS), programmable logic controllers (PLC), supervisory control and data acquisition (SCADA) systems, human-machine interfaces (HMI), remote terminal units (RTU), intelligent electronic devices (IED), sensors, actuators, and other field devices. The control system may also use commercial off-the-shelf (COTS) software and hardware, such as operating systems, databases, firewalls, routers, switches, and servers, to support the control functions and communication.

References:

• ISA/IEC 62443-1-1:2009, Security for industrial automation and control systems - Part 1-1: Terminology, concepts and models, Clause 3.2.11
• ISA/IEC 62443-2-1:2010, Security for industrial automation and control systems - Part 2-1: Establishing an industrial automation and control systems security program, Clause 3.2.12

The application layer is the topmost layer of the OSI model, which provides the interface between the user and the network. It includes protocols specific to network applications such as email, file transfer, and reading data registers in a PLC. These protocols deliver and format information, possibly with encryption and security, to ensure reliable and meaningful communication between different applications. The application layer does not include user applications, which are separate from the network protocols. The application layer also does not provide the mechanism for opening, closing, and managing a session between end-user application processes, which is the function of the session layer. References:

• ISA/IEC 62443 Cybersecurity Fundamentals Specialist Study Guide, page 181
• Using the ISA/IEC 62443 Standards to Secure Your Control System, page 82

The application layer in network protocols, such as in the OSI model or the TCP/IP protocol suite, is primarily responsible for providing services directly to user applications. This layer is involved in:

• Option A: Including protocols specific to network applications such as email, file transfer, and industrial protocols like reading data registers in a Programmable Logic Controller (PLC). This is a core function of the application layer as it facilitates specific high-level networking capabilities.
• Option D: Delivering and formatting information, which can include encryption and ensuring the security of data as it is transmitted across the network. This includes protocols like HTTP for web browsing which can encrypt data via HTTPS, SMTP for secure email transmission, and FTP for secure file transfer.

According to the ISA/IEC 62443-2-1 standard, a review of the CSMS should be triggered by any changes that affect the cybersecurity risk of the industrial automation and control system (IACS), such as new technical controls, organizational restructuring, or security incidents1. Budgeting is not a trigger for CSMS review, unless it impacts the cybersecurity risk level or the CSMS itself2. References: 1: ISA/IEC 62443-2-1:2010, Section 4.3.3.3 2: A Practical Approach to Adopting the IEC 62443 Standards, ISAGCA Blog3

 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 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

 A recommended default rule for IACS firewalls is to block all traffic by default, and then allow only the necessary and authorized traffic based on the security policy and the zone and conduit model. This is also known as the principle of least privilege, which means granting the minimum access required for a legitimate purpose. Blocking all traffic by default provides a higher level of security and reduces the attack surface of the IACS network. The other choices are not recommended default rules for IACS firewalls, as they may expose the IACS network to unnecessary risks. Allowing all traffic by default would defeat the purpose of a firewall, as it would not filter any malicious or unwanted traffic. Allowing IACS devices to access the Internet would expose them to potential cyber threats, such as malware, phishing, or denial-of-service attacks. Allowing traffic directly from the IACS network to the enterprise network would bypass the demilitarized zone (DMZ), which is a buffer zone that isolates the IACS network from the enterprise network and hosts services that need to communicate between them. References:

• ISA/IEC 62443 Standards to Secure Your Industrial Control System training course1
• ISA/IEC 62443 Cybersecurity Fundamentals Specialist Study Guide2
• Using the ISA/IEC 62443 Standard to Secure Your Control Systems3

The ISA-99/IEC 62443 standards for industrial automation and control systems security categorize network and system components into different levels based on their operational context. The correct name from the provided options for one of these levels is Level 3: Operations Management. This level typically encompasses systems that manage production control systems, including batch management, production scheduling, and overall factory operations. The other levels listed, such as Supervisory Control and Process, refer to different aspects of the system but are not named correctly in the options provided. Level 1 is correctly referred to as "Basic Control," and Level 4 should be "Business Logistics" instead of "Process."

In ANSI/ISA-99.00.01:2007, which is part of the ISA/IEC 62443 standards, electronic security encompasses both the technical and human aspects of cybersecurity within industrial automated and control systems (IACS). Option B correctly highlights components such as computers, networks, operating systems, applications, and other programmable configurable components which are intrinsic to the system's electronic security framework. Option C is also correct as it includes the personnel, policies, andprocedures which play a crucial role in securing these systems. This emphasizes that security is not only about the technological solutions but also about managing human elements and organizational processes effectively.ISA/IEC 62443 Cybersecurity Fundamentals References:

• ISA/IEC 62443 standards focus on the holistic nature of security which is clearly supported by including both the technological (Option B) and human elements (Option C) in the definition of electronic security.

 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:

The first step in implementing ISO 27001, an international standard for information security management systems (ISMS), is to perform a security risk assessment. This initial step is critical as it helps identify the organization's information assets that could be at risk, assess the vulnerabilities and threats to these assets, and evaluate their potential impacts. This risk assessment forms the foundation for defining appropriate security controls and measures tailored to the organization’s specific needs. Starting with a risk assessment ensures that the security controls implemented are aligned with the actual risks the organization faces, making the ISMS more effective and targeted.ISA/IEC 62443 Cybersecurity Fundamentals References:

• Although ISO 27001 is not part of ISA/IEC 62443, it shares common principles in cybersecurity management by starting with a comprehensive understanding and assessment of security risks, which is a fundamental aspect in both standards for setting up effective security practices.

A security conduit is a logical or physical grouping of communication channels connecting two or more zones that share common security requirements1. A zone is a grouping of systems and components based on their functional, logical, and physical relationship that share common security requirements1. Therefore, a security conduit consists of assets that enable or facilitatecommunication between zones, such as wiring, routers, switches, and network management devices. Controllers, sensors, transmitters, and final control elements are examples of assets that belong to a zone, not a conduit. Ferrous, thickwall, and threaded conduit including raceways are physical structures that may enclose or protect wiring, but they are not part of the communication channels themselves. Power lines, cabinet enclosures, and protective grounds are also not part of the communication channels, but rather provide power or protection to the assets in a zone or a conduit. References: 1: Key Concepts of ISA/IEC 62443: Zones & Security Levels | Dragos

Security zones are logical groupings of assets that share common security requirements based on factors such as criticality, consequence, vulnerability, and threat. Security zones are used to apply the principle of defense in depth, which means creating multiple layers of protection to prevent or mitigate cyberattacks. By creating security zones, asset owners can isolate the most critical or sensitive assets from the less critical or sensitive ones, and apply different levels of security controls to each zone according to the risk assessment. Security zones are not necessarily aligned with physical network segments, as assets within the same network may have different security requirements. For example, a network segment may contain both a safety instrumented system (SIS) and a human-machine interface (HMI), but the SIS has a higher security requirement than the HMI. Therefore, the SIS and the HMI should be in different security zones, even if they are in the same network segment. Similarly, assets within the same logical communication network may not have the same security requirements, and therefore should not be in the same security zone. For example, a logical communication network may span across multiple physical locations, such as a plant and a corporate office, but the assets in the plant may have higher security requirements than the assets in the office. Therefore, the assets in the plant and the office should be in different security zones, even if they are in the same logical communication network. Finally, all components in a large or complex system should not be in the same security zone, as this would create a single point of failure and expose the entire system to potential cyberattacks. Instead, the components should be divided into smaller and simpler security zones, based on their security requirements, and the communication between the zones should be controlled by conduits. Conduits are logical or physical connections between security zones that allow data flow and access control. Conduits should be designed to minimize the attack surface and the potential impact of cyberattacks, by applying security controls such as firewalls, encryption, authentication, and authorization. References:

• How to Define Zones and Conduits1
• Securing industrial networks: What is ISA/IEC 62443?2
• ISA/IEC 62443 Series of Standards3