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Control Acronym



Security Assessment

CMMC Level


800-171 Control #


CMMC Description

Periodically assess the security controls in organizational systems to determine if the controls are effective in their application.

CMMC Clarification

As organizations implement security controls, they should avoid a “set it and forget it” mentality. The security landscape is constantly changing. Reassess existing controls at periodic intervals in order to validate their usefulness in organizational systems. This will let you determine if the control is still meeting the needs of the organization. Set the assessment schedule according to organizational needs. Consider regulatory obligations and internal policies when assessing the controls. Typical outputs of the practice include: * documented assessment results * proposed new controls, or updates to existing controls * remediation plans * new identified risks. Example You are in charge of IT operations in your company. You ensure that security controls are achieving their objectives. After you implement the controls, you monitor their performance. You should perform this review as often as necessary to meet: * your organization’s risk planning needs * any regulations or policies you must follow. * When you assess the controls, document what you find. When you find your controls are not meeting your requirements, you should act and make changes. You can: * propose updated or new controls * develop a plan to improve the control * document new risks that you find. You should also document these actions.

800-171 Description

Periodically assess the security controls in organizational systems to determine if the controls are effective in their application.

800-171 Discussion

Organizations assess security controls in organizational systems and the environments in which those systems operate as part of the system development life cycle. Security controls are the safeguards or countermeasures organizations implement to satisfy security requirements. By assessing the implemented security controls, organizations determine if the security safeguards or countermeasures are in place and operating as intended. Security control assessments ensure that information security is built into organizational systems; identify weaknesses and deficiencies early in the development process; provide essential information needed to make risk-based decisions; and ensure compliance to vulnerability mitigation procedures. Assessments are conducted on the implemented security controls as documented in system security plans.Security assessment reports document assessment results in sufficient detail as deemed necessary by organizations, to determine the accuracy and completeness of the reports and whether the security controls are implemented correctly, operating as intended, and producing the desired outcome with respect to meeting security requirements. Security assessment results are provided to the individuals or roles appropriate for the types of assessments being conducted. Organizations ensure that security assessment results are current, relevant to the determination of security control effectiveness, and obtained with the appropriate level of assessor independence. Organizations can choose to use other types of assessment activities such as vulnerability scanning and system monitoring to maintain the security posture of systems during the system life cycle. [SP 800-53] provides guidance on security and privacy controls for systems and organizations. [SP 800-53A] provides guidance on developing security assessment plans and conducting assessments.

Other Source Discussion


CIS Control References

NIST 800-53 Control Ref.

NIST SP 800-53 Rev 4 CA-2

CMMC Derived

NIST CSF Control References

NIST 800-171 References

NIST SP 800-171 Rev 1 3.12.1

Applicable FAR Clause

NIST CSF Control Reference


CERT RMM Reference

Modification of NIST 800-171B Reference

NIST 800-171B Reference

UK NCSCCyber Reference

AS ACSC Reference


Assessment Sub-Criteria 1

CA.2.158.[a] the frequency of security control assessments is defined; and

Assessment Sub-Criteria 2

CA.2.158.[b] security controls are assessed with the defined frequency to determine if the controls are effective in their application.

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