Definition
Separation of duties (SoD) is a fundamental security principle that prevents any single individual from having excessive control or authority over critical processes. It works by dividing a task or transaction into multiple steps, with each step performed by a different person. This division of labor is crucial for preventing fraud, errors, and misuse of privileges, as it ensures that no one person can complete a malicious or accidental action without collusion. For instance, one person might create a purchase order, while another approves it and a third processes the payment. A common misconception is that SoD is the same as least privilege, but least privilege grants only necessary permissions, whereas SoD focuses on the distribution of those permissions across multiple individuals. This concept is frequently tested on certifications like Security+, CySA+, and CISSP.