What is the focus of Step 3 of the RMF process?

Step 3 of the Risk Management Framework (RMF) process is centered on assessing the selected security controls for a system. This assessment is essential as it ensures that the controls put in place adequately protect the system's information and can effectively mitigate identified risks. In this step, organizations evaluate how well the controls are functioning, verify that they operate as intended, and determine whether they provide the required level of security for the system's requirements.

During this assessment, various techniques such as testing, evaluation, and documentation review are used to capture the effectiveness of control implementation. This step helps in identifying any weaknesses or gaps in the controls, which can inform further actions and improvements.

In contrast, developing a Plan of Action and Milestones (POAM), documenting control implementation, and registering the system pertain to different aspects of the RMF process. While these might be important in their own right, they are not the focus of Step 3, which is primarily about control assessment and validation.