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

An asymmetric key is a feature of asymmetric cryptography, also known as public-key cryptography, which is a method of encrypting and decrypting data using two different keys: a public key and a private key. The public key can be shared with anyone, while the private key must be kept secret by the owner. The public key and the private key aremathematically related, but it is computationally infeasible to derive one from the other. Asymmetric cryptography can be used for various purposes, such as digital signatures, key exchange, and encryption. For example, if Alice wants to send a message to Bob, she can use Bob’s public key to encrypt the message, and only Bob can decrypt it using his private key. Alternatively, if Bob wants to prove that he is the author of a message, he can use his private key to sign the message, and anyone can verify it using his public key. Asymmetric cryptography has some advantages over symmetric cryptography, which uses the same key for both encryption and decryption. For instance, asymmetric cryptography does not require a secure channel to distribute the keys, and it can provide non-repudiation and authentication. However, asymmetric cryptography also has some drawbacks, such as higher computational complexity, larger key sizes, and higher network overhead.

References:

• ISA/IEC 62443-3-3:2018, Section 4.2.3.6.1, Cryptography1
• ISA/IEC 62443-4-2:2019, Section 4.2.3.6.1, Cryptography
• ISA/IEC 62443 Cybersecurity Fundamentals Specialist Study Guide, Section 5.3.1, Cryptography
• ISA/IEC 62443 Cybersecurity Fundamentals Specialist Exam Specification, Section 5.3.1, Cryptography

Packet filter firewalls, as defined by ISA/IEC 62443 standards on cybersecurity, primarily examine the source, destination, and ports in the header of each packet. This type of firewall does not inspect the packet content deeply (such as its structure or sequence) or maintain awareness of the relationships between packets in a session. Instead, it operates at a more superficial level, filtering packets based solely on IP addresses and TCP/UDP ports. This approach allows packet filter firewalls to quickly process and either accept or block packets based on these predefined criteria without delving into the complexities of session management or the content of the packets up to the application layer.

OPC stands for Open Platform Communications, and it is a series of standards and specifications for industrial telecommunication based on Object Linking and Embedding (OLE) for process control. It allows the communication of real-time data between devices from different manufacturers using various data transportation technologies, such as Microsoft’s OLE, COM, DCOM, .NET, XML, and TCP123. OPC is not a protocolitself, but rather a standardized approach for data connectivity supported by the OPC Foundation3. OPC is widely used in industrial automation and control systems, as well as other industries, to achieve interoperability and integration between different applications and devices3.

A is incorrect, because OPC is not a field bus protocol, but rather a standard for data exchange between devices that may use different field bus protocols, such as Modbus, Profibus, or Ethernet/IP2. C is incorrect, because OPC is not a serial communications protocol, but rather a standard that can use various data transportation technologies, including serial, Ethernet, or wireless2. D is incorrect, because OPC is not a vendor-specific proprietary protocol, but rather an open standard that can be implemented by any vendor or device that supports the OPC specifications3. References: 1: Open Platform Communications - Wikipedia 2: What is OPC Protocol - The Automization 3: What is OPC? - OPC Foundation

 Access control is the process of granting or denying specific requests to obtain and use information and related information processing services. It is one of the foundational requirements (FRs) of the ISA/IEC 62443 standards for securing industrial automation and control systems (IACSs). According to the ISA/IEC 62443-3-3 standard, access control includes the following system requirements (SRs):

• SR 1.1: Identification and authentication control
• SR 1.2: Use control
• SR 1.3: System integrity
• SR 1.4: Data confidentiality
• SR 1.5: Restricted data flow
• SR 1.6: Timely response to events
• SR 1.7: Resource availability

Among these SRs, the ones that are most related to the critical variables of account management and password strength are SR 1.1 and SR 1.2. SR 1.1 requires that the IACS shall provide the capability to uniquely identify and authenticate all users, processes, and devices that attempt to establish a logical connection to the system. This means that the IACS should have a robust account management system that can create, modify, delete, and monitor user accounts and their privileges. It also means that the IACS should enforce strong password policies that can prevent unauthorized access or compromise of user credentials. Password strength refers to the level of difficulty for an attacker to guess or crack a password. It depends on factors such as length, complexity, randomness, and uniqueness of the password.

SR 1.2 requires that the IACS shall provide the capability to enforce the use of logical connections in accordance with the security policy of the organization. This means that the IACS should have a mechanism to control the access rights and permissions of users, processes, and devices based on their roles, responsibilities, and needs. It also means that the IACS should have a mechanism to audit and log the activities and events related to access control, such as successful or failed login attempts, password changes, privilege escalations, or unauthorized actions.

Therefore, account management and password strength are the critical variables related to access control, as they directly affect the identification, authentication, and authorization of users, processes, and devices in 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 Cybersecurity Fundamentals Specialist Certificate Program2
• ISA/IEC 62443 Cybersecurity Library3
• Using the ISA/IEC 62443 Standards to Secure Your Control Systems4