Step 4: Assess Security Controls
Develop, review, and approve a plan to assess the security controls.
The security assessment plan provides the objectives for the security control assessment, a detailed roadmap of how to conduct such an assessment, and assessment procedures. The assessment plan reflects the type of assessment the organization is conducting (e.g., developmental testing and evaluation, independent verification and validation, assessments supporting security authorizations or reauthorizations, audits, continuous monitoring, assessments subsequent to remediation actions). Conducting security control assessments in parallel with the development/acquisition and implementation phases of the life cycle permits the identification of weaknesses and deficiencies early 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 security control assessments carried out during system development and implementation can also be used (consistent with reuse criteria) during the security authorization process to avoid system fielding delays or costly repetition of assessments. The security assessment plan is reviewed and approved by appropriate organizational officials to ensure that the plan is consistent with the security objectives of the organization, employs state-of-the practice tools, techniques, procedures, and automation to support the concept of continuous monitoring and near real-time risk management, and is cost- effective with regard to the resources allocated for the assessment. The purpose of the security assessment plan approval is two-fold: (i) to establish the appropriate expectations for the security control assessment; and (ii) to bound the level of effort for the security control assessment. An approved security assessment plan helps to ensure that an appropriate level of resources is applied toward determining security control effectiveness. When security controls are provided to an organization by an external provider (e.g., through contracts, interagency agreements, lines of business arrangements, licensing agreements, and/or supply chain arrangements), the organization obtains a security assessment plan from the provider.
Organizations consider both the technical expertise and level of independence required in selecting security control assessors. Organizations also ensure that security control assessors possess the required skills and technical expertise to successfully carry out assessments of system-specific, hybrid, and common controls. This includes knowledge of and experience with the specific hardware, software, and firmware components employed by the organization. An independent assessor is any individual or group capable of conducting an impartial assessment of security controls employed within or inherited by an information system. Impartiality implies that assessors are free from any perceived or actual conflicts of interest with respect to the development, operation, and/or management of the information system or the determination of security control effectiveness. Independent security control assessment services can be obtained from other elements within the organization or can be contracted to a public or private sector entity outside of the organization. Contracted assessment services are considered independent if the information system owner is not directly involved in the contracting process or cannot unduly influence the independence of the assessor(s) conducting the assessment of the security controls. The authorizing official or designated representative determines the required level of independence for security control assessors based on the results of the security categorization process for the information system and the ultimate risk to organizational operations and assets, individuals, other organizations, and the Nation. The authorizing official determines if the level of assessor independence is sufficient to provide confidence that the assessment results produced are sound and can be used to make a risk-based decision on whether to place the information system into operation or continue its operation. In special situations, for example when the organization that owns the information system is small or the organizational structure requires that the security control assessment be accomplished by individuals that are in the developmental, operational, and/or management chain of the system owner, independence in the assessment process can be achieved by ensuring that the assessment results are carefully reviewed and analyzed by an independent team of experts to validate the completeness, consistency, and veracity of the results. The authorizing official consults with the Office of the Inspector General, the senior information security officer, and the chief information officer to discuss the implications of any decisions on assessor independence in the types of special circumstances described above. This discussion may occur prior to each security assessment or only once if an organization is establishing an organizational policy and approach for specific special circumstances that will be applied to all information systems meeting the specific special circumstance criteria. Security control assessments in support of initial and subsequent security authorizations are conducted by independent assessors.
Assess the security controls in accordance with the assessment procedures defined in the security assessment plan.
Security control assessments determine the extent to which the controls are implemented correctly, operating as intended, and producing the desired outcome with respect to meeting the security requirements for the information system. Security control assessments occur as early as practicable in the system development life cycle, preferably during the development phase of the information system. These types of assessments are referred to as developmental testing and evaluation and are intended to validate that the required security controls are implemented correctly and consistent with the established information security architecture. Developmental testing and evaluation activities include, for example, design and code reviews, application scanning, and regression testing. Security weaknesses and deficiencies identified early in the system development life cycle can be resolved more quickly and in a much more cost-effective manner before proceeding to subsequent phases in the life cycle. The objective is to identify the information security architecture and security controls up front and to ensure that the system design and testing validate the implementation of these controls.
The information system owner relies on the technical expertise and judgment of assessors to: (i) assess the security controls employed within or inherited by the information system using assessment procedures specified in the security assessment plan; and (ii) provide specific recommendations on how to correct weaknesses or deficiencies in the controls and reduce or eliminate identified vulnerabilities. The assessor findings are an unbiased, factual reporting of the weaknesses and deficiencies discovered during the security control assessment. Organizations are encouraged to maximize the use of automation to conduct security control assessments to help: (i) increase the speed and overall effectiveness and efficiency of the assessments; and (ii) support the concept of ongoing monitoring of the security state of organizational information systems. When iterative development processes such as agile development are employed, this typically results in an iterative assessment as each cycle is conducted. A similar process is used for assessing security controls in COTS information technology products employed within the information system. Even when iterative development is not employed, organizations may choose to begin assessing security controls prior to the complete implementation of all security controls listed in the security plan. This type of incremental assessment is appropriate if it is more efficient or cost-effective to do so. For example, policy, procedures, and plans may be assessed prior to the assessment of the technical security controls in the hardware and software. In many cases, common controls (i.e., security controls inherited by the information system) may be assessed prior to the security controls employed within the system.
The organization ensures that assessors have access to: (i) the information system and environment of operation where the security controls are employed; and (ii) the appropriate documentation, records, artifacts, test results, and other materials needed to assess the security controls. In addition, assessors have the required degree of independence as determined by the authorizing official (see Appendix D.13 and Appendix F.4). Security control assessments in support of initial and subsequent security authorizations are conducted by independent assessors. Assessor independence during continuous monitoring, although not mandated, facilitates reuse of assessment results when reauthorization is required. When security controls are provided to an organization by an external provider (e.g., through contracts, interagency agreements, lines of business arrangements, licensing agreements, and/or supply chain arrangements), the organization ensures that assessors have access to the information system/environment of operation where the controls are employed as well as appropriate information needed to carry out the assessment. The organization also obtains any information related to existing assessments that may have been conducted by the external provider and reuses such assessment information whenever possible in accordance with the reuse criteria established by the organization. Descriptive information about the information system is typically documented in the system identification section of the security plan or included by reference or as attachments to the plan. Supporting materials such as procedures, reports, logs, and records showing evidence of security control implementation are identified as well. In order to make the risk management process as timely and cost-effective as possible, the reuse of previous assessment results, when reasonable and appropriate, is strongly recommended. For example, a recent audit of an information system may have produced information about the effectiveness of selected security controls. Another opportunity to reuse previous assessment results comes from programs that test and evaluate the security features of commercial information technology products. Additionally, if prior assessment results from the system developer are available, the security control assessor, under appropriate circumstances, may incorporate those results into the assessment. And finally, assessment results are reused to support reciprocity where possible.
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.
Prepare the security assessment report documenting the issues, findings, and recommendations from the security control assessment.
The results of the security control assessment, including recommendations for correcting any weaknesses or deficiencies in the controls, are documented in the security assessment report. The security assessment report is one of three key documents in the security authorization package developed for authorizing officials. The assessment report includes information from the assessor necessary to determine the effectiveness of the security controls employed within or inherited by the information system based upon the assessor’s findings. The security assessment report is an important factor in an authorizing official’s determination of risk to organizational operations and assets, individuals, other organizations, and the Nation. Security control assessment results are documented at a level of detail appropriate for the assessment in accordance with the reporting format prescribed by organizational and/or federal policies. The reporting format is also appropriate for the type of security control assessment conducted (e.g., developmental testing and evaluation, self-assessments, independent verification and validation, independent assessments supporting the security authorization process or subsequent reauthorizations, assessments during continuous monitoring, assessments subsequent to remediation actions, independent audits/evaluations).
Security control assessment results obtained during system development are brought forward in an interim report and included in the final security assessment report. This supports the concept that the security assessment report is an evolving document that includes assessment results from all relevant phases of the system development life cycle including the results generated during continuous monitoring. Organizations may choose to develop an executive summary from the detailed findings that are generated during a security control assessment. An executive summary provides an authorizing official with an abbreviated version of the assessment report focusing on the highlights of the assessment, synopsis of key findings, and/or recommendations for addressing weaknesses and deficiencies in the security controls.
Conduct initial remediation actions on security controls based on the findings and recommendations of the security assessment report and reassess remediated control(s), as appropriate.
The security assessment report provides visibility into specific weaknesses and deficiencies in the security controls employed within or inherited by the information system that could not reasonably be resolved during system development. The findings generated during the security control assessment facilitate a disciplined and structured approach to mitigating risks in accordance with organizational priorities. Information system owners and common control providers, in collaboration with selected organizational officials (e.g., information system security engineer, authorizing official designated representative, chief information officer, senior information security officer, information owner/steward), may decide that certain findings are inconsequential and present no significant risk to the organization. Alternatively, the organizational officials may decide that certain findings are in fact, significant, requiring immediate remediation actions. In all cases, organizations review assessor findings and determine the severity or seriousness of the findings (i.e., the potential adverse impact on organizational operations and assets, individuals, other organizations, or the Nation) and whether the findings are sufficiently significant to be worthy of further investigation or remediation. An updated assessment of risk (either formal or informal) based on the results of the findings produced during the security control assessment and any inputs from the risk executive (function), helps to determine the initial remediation actions and the prioritization of such actions. Senior leadership involvement in the mitigation process may be necessary in order to ensure that the organization’s resources are effectively allocated in accordance with organizational priorities, providing resources first to the information systems that are supporting the most critical and sensitive missions and business functions for the organization or correcting the deficiencies that pose the greatest degree of risk. If weaknesses or deficiencies in security controls are corrected, the remediated controls are reassessed for effectiveness. Security control reassessments determine the extent to which the remediated controls are implemented correctly, operating as intended, and producing the desired outcome with respect to meeting the security requirements for the information system. Exercising caution not to change the original assessment results, assessors update the security assessment report with the findings from the reassessment. The security plan is updated based on the findings of the security control assessment and any remediation actions taken. The updated security plan reflects the actual state of the security controls after the initial assessment and any modifications by the information system owner or common control provider in addressing recommendations for corrective actions. At the completion of the assessment, the security plan contains an accurate list and description of the security controls implemented (including compensating controls) and a list of residual vulnerabilities.
Organizations can prepare an optional addendum to the security assessment report that is transmitted to the authorizing official. The optional addendum provides information system owners and common control providers an opportunity to respond to the initial findings of assessors. The addendum may include, for example, information regarding initial remediation actions taken by information system owners or common control providers in response to assessor findings, or provide an owner’s perspective on the findings (e.g., including additional explanatory material, rebutting certain findings, and correcting the record). The addendum to the security assessment report does not change or influence in any manner, the initial assessor findings provided in the original report. Information provided in the addendum is considered by authorizing officials in their risk-based authorization decisions. Organizations may choose to employ an issue resolution process to help determine the appropriate actions to take with regard to the security control weaknesses and deficiencies identified during the assessment. Issue resolution can help address vulnerabilities and associated risk, false positives, and other factors that may provide useful information to authorizing officials regarding the security state of the information system including the ongoing effectiveness of system-specific, hybrid, and common controls. The issue resolution process can also help to ensure that only substantive items are identified and transferred to the plan of actions and milestones.