Final answer:
To best support the availability of an industrial control system, a security analyst should implement security controls with redundancy and fault tolerance, along with regular updates and monitoring. It's also critical to account for human factors that impact security decision-making.
Step-by-step explanation:
To ensure the availability of a critical industrial control system, it is best for a security analyst to implement robust security controls that promote system uptime and reduce the risk of downtime due to malicious attacks or failures. This can be done by incorporating redundancy, robust fault tolerance measures, and implementing a comprehensive disaster recovery plan.
Moreover, the analyst should consider regular system updates, performing security audits, and ensuring proper monitoring to quickly identify and address issues.
A practical example of the importance of system availability and the impact of human factors on security can be found in the study conducted by Bruno & Abrahão (2012), which highlights the correlation between cognitive effort of operators and the accuracy of decisions within an information security center. Given this context, it is crucial to not only focus on technical measures but also to consider the human factors psychology that may influence the operation of security controls.