Phishing is a type of cyberattack that relies on a human weakness to succeed. Phishing is the practice of sending fraudulent emails or other messages that appear to come from a legitimate source, such as a bank, a government agency, or a trusted person, in order to trick the recipient into revealing sensitive information, such as passwords, credit card numbers, or personal details, or into clicking on malicious links or attachments that may install malware or ransomware on their devices. Phishing is a common and effective way of compromising the security of industrial automation and control systems (IACS), as it can bypass technical security measures by exploiting the human factor. Phishing can also be used to gain access to the IACS network, to conduct reconnaissance, to launch further attacks, or to cause damage or disruption to the IACS operations. The ISA/IEC 62443 series of standards recognize phishing as a potential threat vector for IACS and provide guidance and best practices on how to prevent, detect, and respond to phishing attacks. Some of the recommended countermeasures include:
* Educating and training the IACS staff on how to recognize and avoid phishing emails and messages, and how to report any suspicious or malicious activity.
* Implementing and enforcing policies and procedures for email and message security, such as using strong passwords, verifying the sender's identity, and not opening or clicking on unknown or unsolicited links or attachments.
* Applying technical security controls, such as antivirus software, firewalls, spam filters, encryption, and authentication, to protect the IACS devices and network from phishing attacks.
* Monitoring and auditing the IACS network and devices for any signs of phishing attacks, such as
* anomalous or unauthorized traffic, connections, or activities, and taking appropriate actions to contain and mitigate the impact of any incidents. References:
* ISA/IEC 62443-1-1:2009, Security for industrial automation and control systems - Part 1-1:
Terminology, concepts and models1
* 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 62443-2-4:2015, Security for industrial automation and control systems - Part 2-4: Security program requirements for IACS service providers3
* ISA/IEC 62443-3-3:2013, Security for industrial automation and control systems - Part 3-3: System security requirements and security levels4
* ISA/IEC 62443-4-2:2019, Security for industrial automation and control systems - Part 4-2: Technical security requirements for IACS components5

According to the IEC 62443 standard, a capability security level (SL-C) is defined as "the security level that a component or system is capable of meeting when it is properly configured and protected by an appropriate set of security countermeasures" 1. A component or system can have different SL-Cs for different security requirements, depending on its design and implementation. The SL-C is determined by testing the component or system against a set of security test cases that correspond to the security requirements. The SL-C is not dependent on the actual operational environment orconfiguration of the component or system, but rather on its inherent capabilities. References:
* IEC 62443 - Wikipedia