Step 3: Implement Security Controls
Implement the security controls specified in the security plan.
Security control implementation is consistent with the organization’s enterprise architecture and information security architecture. The information security architecture serves as a resource to allocate security controls (including, for example, security mechanisms and services) to an information system and any organization- defined subsystems. Security controls targeted for deployment within the information system (including subsystems) are allocated to specific system components responsible for providing a particular security capability. Not all security controls need to be allocated to every subsystem. Categorization of subsystems, information security architecture, and allocation of security controls work together to help achieve a suitable balance. Allocating some security controls as common controls or hybrid controls is part of this architectural process. Organizations use best practices when implementing the security controls within the information system including system and software engineering methodologies, security engineering principles, and secure coding techniques. In addition, organizations ensure that mandatory configuration settings are established and implemented on information technology products in accordance with federal and organizational policies (e.g., Federal Desktop Core Configuration). Information system security engineers with support from information system security officers employ a sound security engineering process that captures and refines information security requirements and ensures the integration of those requirements into information technology products and systems through purposeful security design or configuration. When available, organizations consider the use of information technology products that have been tested, evaluated, or validated by approved, independent, third-party assessment facilities. In addition, organizations satisfy, where applicable, minimum assurance requirements when implementing security controls. Assurance requirements are directed at the activities and actions that security control developers and implementers define and apply to increase the level of confidence that the controls are implemented correctly, operating as intended, and producing the desired outcome with respect to meeting the security requirements for the information system. Assurance requirements address the quality of the design, development, and implementation of the security functions in the information system. For higher-impact systems (i.e., potential high-value targets) in situations where specific and credible threat information indicates the likelihood of advanced cyber attacks, additional assurance measures are considered. Organizations consider any implementation- related issues associated with the integration and/or interfaces among common controls and system-specific controls.
For the identified common controls inherited by the information system, information system security engineers with support from information system security officers coordinate with the common control provider to determine the most appropriate way to apply the common controls to the organizational information systems. For certain management and operational controls, formal integration into information technology products, services, and systems may not be required. For certain types of operational and/or technical controls, implementation may require additional components, products, or services to enable the information system to utilize the previously selected common controls to the fullest extent. If selection of common controls previously had been deferred, identification of common controls inherited by the information system is revisited to determine if better determinations can be made at this point in the system development life cycle. Information system owners can refer to the authorization packages prepared by common control providers when making determinations regarding the adequacy of the implementations of common controls for their respective systems. For common controls that do not meet the protection needs of the information systems inheriting the controls or that have unacceptable weaknesses or deficiencies, the system owners identify compensating or supplementary controls to be implemented. To the maximum extent and consistent with the flexibility allowed in applying the tasks in the RMF, organizations and their contractors conduct initial security control assessments (also referred to as developmental testing and evaluation) during information system development and implementation. Conducting security control assessments in parallel with the development and implementation phases of the system development life cycle facilitates the early identification of weaknesses and deficiencies and provides the most cost-effective method for initiating corrective actions. Issues found during these assessments can be referred to authorizing officials for early resolution, as appropriate. The results of the initial security control assessments can also be used during the security authorization process to avoid delays or costly repetition of assessments. Assessment results that are subsequently reused in other phases of the system development life cycle meet the reuse requirements (including independence) established by the organization.
Document the security control implementation, as appropriate, in the security plan, providing a functional description of the control implementation (including planned inputs, expected behavior, and expected outputs).
Security control documentation describes how system-specific,hybrid, and commoncontrols are implemented. The documentation formalizes plans and expectations regarding the overall functionality of the information system. The functional description of the security control implementation includes planned inputs, expected behavior, and expected outputs where appropriate, typically for those technical controls that are employed in the hardware, software, or firmware components of the information system. Documentation of security control implementation allows for traceability of decisions prior to and after deployment of the information system. The level of effort expended on documentation of the information system is commensurate with the purpose, scope, and impact of the system with respect to organizational missions, business functions, and operations. To the extent possible, organizations reference existing documentation (either by vendors or other organizations that have employed the same or similar information systems), use automated support tools, and maximize communications to increase the overall efficiency and cost effectiveness of security control implementation. The documentation also addresses platform dependencies and includes any additional information necessary to describe how the security capability required by the security control is achieved at the level of detail sufficient to support control assessment. Documentation for security control implementation follows best practices for hardware and software development as well as for system/security engineering disciplines and is consistent with established organizational policies and procedures for documenting system development life cycle activities. Whenever possible and practicable for technical security controls that are mechanism-based, organizations take maximum advantage of functional specifications provided by or obtainable from hardware and software vendors and/or systems integrators including security-relevant documentation that may assist the organization during the assessment and monitoring of the controls. Similarly, for management and operational controls, organizations obtain security control implementation information from appropriate organizational entities (e.g., facilities offices, human resource offices, physical security offices). Since the enterprise architecture and information security architecture established by the organization significantly influence the approach used to implement security controls, providing documentation of this process helps to ensure traceability with regard to meeting the organization’s information security requirements.
Common controls are security controls that are inherited by one or more organizational information systems. Common controls are identified by the chief information officer and/or senior information security officer in collaboration with the information security architect and assigned to specific organizational entities (designated as common control providers) for development, implementation, assessment, and monitoring. Common control providers may also be information system owners when the common controls are resident within an information system. The organization consults information system owners when identifying common controls to ensure that the security capability provided by the inherited controls is sufficient to deliver adequate protection. When the common controls provided by the organization are not sufficient for information systems inheriting the controls, the system owners supplement the common controls with system-specific or hybrid controls to achieve the required protection for the system and/or accept greater risk. Information system owners inheriting common controls can either document the implementation of the controls in their respective security plans or reference the controls contained in the security plans of the common control providers. Organizations may choose to defer common control identification and security control selection until a later phase in the system development life cycle. When common controls are not resident within an information system (e.g., physical and environmental protection controls, personnel security controls), the organization selects one or more senior organizational officials or executives to serve as authorizing officials for those controls. These authorizing officials are responsible for accepting the risk to organizational operations and assets, individuals, other organizations, and the Nation resulting from the deployment of the security controls provided by common control providers and inherited by organizational information systems. Common control providers are responsible for: (i) documenting common controls in a security plan (or equivalent document prescribed by the organization); (ii) ensuring that common controls are developed, implemented, and assessed for effectiveness by qualified assessors with a level of independence required by the organization; (iii) documenting assessment findings in a security assessment report; (iv) producing a plan of action and milestones for all common controls deemed less than effective (i.e., having unacceptable weaknesses or deficiencies in the controls); (v) receiving authorization for the common controls from the designated authorizing official; and (vi) monitoring common control effectiveness on an ongoing basis.
Security plans, security assessment reports, and plans of action and milestones for common controls (or a summary of such information) are made available to information system owners (whose systems are inheriting the controls) after the information is reviewed and approved by the senior official or executive responsible and accountable for the controls. The organization ensures that common control providers keep this information current since the controls typically support multiple organizational information systems. Security plans, security assessment reports, and plans of action and milestones for common controls are used by authorizing officials within the organization to make risk-based decisions in the security authorization process for their information systems. The use of common controls is documented within the security plans for information systems inheriting those controls. Organizations ensure that common control providers have the capability to rapidly broadcast changes in the status of common controls that adversely affect the protections being provided by and expected of the common controls. Common control providers are able to quickly inform information system owners when problems arise in the inherited common controls (e.g., when an assessment or reassessment of a common control indicates the control is flawed in some manner, when a new threat or attack method arises that renders the common control less than effective in protecting against the new threat or attack method). Organizations are encouraged, when feasible, to employ automated management systems to maintain records of the specific common controls used in each organizational information system to enhance the ability of common control providers to rapidly communicate with information system owners. If common controls are provided to the organization (and its information systems) by entities external to the organization (e.g., shared and/or external service providers), arrangements are made with the external/shared service providers by the organization to obtain information on the effectiveness of the deployed controls. Information obtained from external organizations regarding the effectiveness of common controls is factored into authorization decisions.