Final answer:
The best method for a CISO to assess and improve the security team's response times to potential data breaches with minimal disruption is to conduct a tabletop exercise. This approach provides a controlled environment to practice the response to a simulated attack, thereby improving the team's preparedness.
Step-by-step explanation:
To address concerns about reactive measures to a potential future data breach, the most effective method to test and improve incident response times with minimal disruption is C. Conduct a tabletop exercise. Tabletop exercises involve a simulated cybersecurity incident where the security team, guided by the new Chief Information Security Officer (CISO), can role-play a response to an attack.
It is a strategic way of validating the incident response plan, identifying gaps in protocols, and enhancing the team's ability to respond quickly and effectively.
Unlike a black box assessment or recreating the previous breach, which could be time-consuming and potentially disruptive, a tabletop exercise is a more controlled environment. It focuses on improving communication and coordination without the risk of inadvertently causing actual harm to the company's systems.
While an external red team audit or an external vulnerability assessment could help in identifying weaknesses, they do not specifically address response time or team preparedness in the face of an actual incident.
Therefore, The best method to achieve the goal of reacting to a future attack while minimizing disruption is to C. Conduct a tabletop exercise.