Who is responsible for defining roles and responsibilities for information security within an organization?

The responsibility for defining roles and responsibilities for information security within an organization primarily falls on top management. This is because top management plays a crucial role in establishing the overall direction and commitment to information security as part of the organization's governance framework. They are responsible for ensuring that there is a clear definition of roles to support the implementation of effective security measures aligned with the organization's objectives.

Top management's involvement is essential for fostering a culture of security, allocating necessary resources, and ensuring that everyone understands their roles in protecting information assets. They set the tone for the organization’s security posture and are responsible for making strategic decisions that shape the organization’s approach to risk management, policy development, and compliance with standards like ISO 27001.

Mid-level management, while important in operationalizing these roles and implementing policies on a day-to-day basis, does not hold the ultimate authority to define roles at the organizational level. The IT department typically focuses on the technical implementation and management of information security measures rather than defining overarching responsibilities. External auditors primarily assess compliance and effectiveness rather than establish roles. Thus, top management is best positioned to lead and define these critical roles and responsibilities in information security.