Explanation
The information security manager should do FIRST invoke the organization's incident response plan, which is a predefined set of procedures and guidelines for handling security incidents in a timely and effective manner.
The incident response plan should include the roles and responsibilities of the incident response team, the communication protocols and channels, the escalation and reporting procedures, and the documentation and evidence collection requirements. By invoking the incident response plan, the information security manager can ensure that the incident is properly contained, analyzed, resolved, and reported, and that the appropriate stakeholders are informed and involved. The other options are not the first actions that the information security manager should take, as they are part of the communication process that follows the incident response plan.
Setting up communication channels for the target audience, determining the needs and requirements of each audience, and creating a comprehensive singular communication are all important steps for communicating effectively with the board, regulatory agencies, and the media, but they are not the first priority in the event of a security incident. The information security manager should first follow the incident response plan to manage the incident and its impact, and then communicate the relevant information to the target audience according to the plan. References = CISM Review Manual, 16th Edition, page 2261; CISM Review Questions, Answers & Explanations Manual, 10th Edition, page 1012 Determining the needs and requirements of each audience should be the FIRST step in developing materials to update the board, regulatory agencies, and the media about a security incident. This is because different audiences have different expectations, interests, and concerns regarding the incident and its impact. By understanding the needs and requirements of each audience, the information security manager can tailor the communication materials to address them effectively and appropriately. This will also help to avoid confusion, misinformation, or misinterpretation of the incident details and response actions