NIST SP 800-171: Strengthening Personnel Security to Protect CUI

As government contractors, meeting the requirements of NIST SP 800-171 isn’t just a recommendation—it’s a necessity. Compliance with these security controls is critical for protecting Controlled Unclassified Information (CUI) and ensuring uninterrupted business operations. One of the framework’s key areas focuses on Personnel Security, ensuring that only trusted individuals can access sensitive systems and that access is promptly revoked or adjusted during personnel changes.

Personnel security is a critical pillar of a strong cybersecurity posture. It ensures that only authorized and trustworthy individuals can access CUI, reducing the risk of insider threats and accidental data exposure. This control also requires organizations to manage access during employee departures or role changes, preventing lingering permissions that could be exploited.

Breaking Down NIST SP 800-171’s Personnel Security Requirements

Screening Individuals Before Granting Access (3.9.1)

Before authorizing access to systems containing CUI, organizations must thoroughly screen individuals. This involves role-based access management and evaluating personnel based on:

• Conduct: Assessing behavioral history and ethical standards

• Integrity: Ensuring honesty and adherence to security policies

• Judgment: Evaluating decision-making capabilities under pressure

• Loyalty: Determining commitment to organizational objectives

• Reliability: Verifying consistency and dependability

• Stability: Considering emotional and mental steadiness

Thorough screening reduces the likelihood of granting access to individuals who may pose a security risk.

Protecting CUI During and After Personnel Changes (3.9.2)

Maintaining CUI security doesn’t stop at access approval—it continues through ongoing personnel management. Organizations must enforce strict controls during employee terminations, departures, and role transfers, including:

• Offboarding Departing Employees:

  • Conduct exit interviews to reinforce security obligations.

  • Recover system-related property, including ID badges, authentication tokens, keys, and laptops.

  • Immediately disable accounts to prevent post-termination access.

• Managing Internal Transfers:

  • Revoke old access privileges and issue new authorizations based on the employee’s updated role.

  • Replace physical access credentials, such as keys or building passes.

  • Adjust system permissions to reflect new responsibilities, preventing unnecessary access.

  • These processes help prevent former employees or transferred staff from retaining unauthorized access, mitigating potential security risks.

Best Practices for Effective Personnel Security

To fully meet NIST SP 800-171’s personnel security standards, organizations should implement the following practices:

• Regular Access Reviews: Perform periodic audits to verify that only current, authorized personnel have access to CUI.

• Clear Termination Procedures: Standardize and document offboarding processes to ensure consistency.

• Continuous Monitoring: Use automated access controls and real-time alerts to identify suspicious activity tied to inactive or outdated credentials.

• Training and Awareness: Educate employees on the importance of protecting CUI, including their responsibilities before, during, and after employment.

Stay Ahead of the Game: Achieve NIST SP 800-171 Compliance with Total Assure

Total Assure specializes in helping organizations achieve and maintain NIST SP 800-171 compliance through tailored cybersecurity strategies. With expertise in vulnerability management, access controls, and governance, we help you detect and prevent cyber threats while safeguarding sensitive data.

Contact us for a free consultation on developing a Personnel Security Plan that meets NIST SP 800-171 requirements and protects your business from unauthorized access.