Fiduciary duty is a legal and ethical obligation to act carefully and in the best interests of another party, especially when you control their assets, systems, or access. In cyber security, that means decision-makers cannot treat protection as optional background work: they must manage risk, preserve continuity, and avoid preventable harm.
This matters in ransomware and other attacks because the people responsible for a business may inherit weak controls, unclear permissions, or unmanaged backups. If they ignore those issues, they may fail their duty to stakeholders. In practice, fiduciary duty shows up in security reviews, incident planning, access control decisions, and documentation that risk was considered before transfers, restructurings, or operational handoffs. It is both a governance standard and a defense measure.