Cybersecurity ISA-IEC-62443 Updated Exam

 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

 According to the ISA/IEC 62443-2-4 standard, a training and security awareness program should include all personnel who have access to the industrial automation and control system (IACS) or who are involved in its operation, maintenance, or management. This includes vendors and suppliers, employees, temporary staff, contractors, and visitors. The purpose of the program is to ensure that all personnel are aware of the security risks and policies related to the IACS, and that they have the necessary skills and knowledge to perform their roles in a secure manner. The program should also cover the roles and responsibilities of different personnel, the reporting procedures for security incidents, and the best practices for security hygiene. References:

ISA/IEC 62443-2-4:2015 - Security for industrial automation and control systems - Part 2-4: Security program requirements for IACS service providers1

ISA/IEC 62443 Cybersecurity Fundamentals Specialist Training Course2

ISO/IEC 15408, also known as the Common Criteria for Information Technology Security Evaluation, is an international standard that provides a framework for evaluating the security of IT products and systems. The purpose of the standard is to define a common set of requirements for the security functions and assurance measures of IT products and systems, and to establish a common methodology for conducting security evaluations. The standard allows users to specify their security needs and expectations in a Security Target (ST), which may be based on one or more Protection Profiles (PPs) that define security requirements for a class of products or systems. Vendors can then implement or claim compliance with the ST or PPs, and have their products or systems evaluated by independent testing laboratories against the security criteria defined in the standard. The standard also defines a scale of Evaluation Assurance Levels (EALs) that indicate the degree of confidence in the security of the evaluated product or system. The standard is intended to facilitate the development, procurement, and use of secure IT products and systems, and to promote the recognition and acceptance of evaluation results across different countries and regions. References:

ISO/IEC 15408-1:2009 - Common Criteria Evaluation for IT Security - Nemko1

Common Criteria - Wikipedia2

ISO/IEC Standard 15408 — ENISA3

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