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Select the controls for the system and the environment of operation.
Potential Inputs: Security categorization; organization- and system-level risk assessment results; system element information; system component inventory; list of security and privacy requirements allocated to the system, system elements, and environment of operation; list of contractual requirements allocated to external providers of the system or system element; business impact analysis or criticality analysis; risk management strategy; organizational security and privacy policy; federal or organization-approved or mandated baselines or overlays; Cybersecurity Framework Profiles.
Expected Outputs: Controls selected for the system and the environment of operation.
Primary Responsibility: System Owner; Common Control Provider.
Supporting Roles: Authorizing Official or Authorizing Official Designated Representative; Information Owner or Steward; Systems Security Engineer; Privacy Engineer; System Security Officer; System Privacy Officer.
System Development Life Cycle Phase: New – Development/Acquisition. Existing – Operations/Maintenance.
Discussion: There are two approaches that can be used for the initial selection of controls: a baseline control selection approach, or an organization-generated control selection approach. The baseline control selection approach uses control baselines, which are pre-defined sets of controls specifically assembled to address the protection needs of a group, organization, or community of interest. Control baselines serve as a starting point for the protection of individuals’ privacy, information, and information systems. Federal control baselines are provided in [SP 800-53B]. The system security categorization (see Task C-2) and the security requirements derived from stakeholder protection needs, laws, executive orders, regulations, policies, directives, instructions, and standards (see Task P-15) can help inform the selection of security control baselines. A privacy risk assessment (see Task P-14) and privacy requirements derived from stakeholder protection needs, laws, executive orders, regulations, policies, directives, instructions, and standards (see Task P-15) can help inform the selection of privacy control baselines. Privacy programs use security and privacy control baselines to manage the privacy risks arising from both unauthorized system activity or behavior, as well as from authorized activities. After the pre-defined control baseline is selected, organizations tailor the baseline in accordance with the guidance provided (see Task S-2). The baseline control selection approach can provide consistency across a broad community of interest.

The organization-generated control selection approach differs from the baseline selection approach because the organization does not start with a pre-defined set of controls. Rather, the organization uses its own selection process to select controls. This may be necessary when the system is highly specialized (e.g., a weapons system or a medical device) or has limited purpose or scope (e.g., a smart meter). In these situations, it may be more efficient and cost-effective for an organization to select a specific set of controls for the system (i.e., a bottom-up approach) instead of starting with a pre-defined set of controls from a broad-based control baseline and subsequently eliminating controls through the tailoring process (i.e., top-down approach).

In both the baseline control selection approach and organization-generated control selection approach, organizations develop a well-defined set of security and privacy requirements using a life cycle-based systems engineering process (e.g., [ISO 15288] and [SP 800-160 v1] as described in the RMF Prepare- System Level step, Task P-15. This process generates a set of requirements that can be used to guide and inform the selection of a set of controls to satisfy the requirements (whether the organization starts with a control baseline or generates the set of controls from its own selection process). Similarly, organizations can use the [NIST CSF] to develop Cybersecurity Framework Profiles representing a set of organization- specific security and privacy requirements—and thus, guiding and informing control selection from [SP 800-53]. Tailoring may also be required in the organization-generated control selection approach (see Task S-2). Organizations do not need to choose one approach for the selection of controls for each of their systems, but instead, may use different approaches as circumstances dictate.

References: [FIPS 199]; [FIPS 200]; [SP 800-30]; [SP 800-53]; [SP 800-53B]; [SP 800-160 v1] (System Requirements Definition, Architecture Definition, and Design Definition Processes); [SP 800-161] (Respond and Chapter 3); [IR 8062]; [IR 8179]; [CNSSI 1253]; [NIST CSF] (Core [Identify, Protect, Detect, Respond, Recover Functions]; Profiles).