Page 32 - Cyber Defense eMagazine July 2024

Implementing Zero Trust Practices

1. Zero Trust Architecture (ZTA):
o NIST SP 800-53 Controls: Implement controls like AC-6 (Least Privilege) and IA-5 (Authenticator
Management) to enforce zero trust principles. This includes ensuring that access is granted based
on the principle of least privilege and is continuously verified.
o RMF Steps: The “Implement” and “Monitor” steps are crucial for deploying and maintaining a zero
trust architecture. Continuous assessment ensures that access controls are effective and that any
deviations are promptly addressed [12][14].

2. Preventing Lateral Movement:

o NIST SP 800-53 Controls: Use controls such as SC-28 (Protection of Information at Rest) and
SC-29 (Heterogeneity) to prevent lateral movement within networks. These controls help in
isolating compromised systems and protecting sensitive data.
o RMF Steps: The “Assess” and “Monitor” steps involve evaluating the effectiveness of these
controls and ensuring that they are continuously enforced to prevent lateral movement [12][14].

Continuous Monitoring

1. Advanced Monitoring Tools:

o NIST SP 800-53 Controls: Implement controls like CA-7 (Continuous Monitoring) and SI-4
(System Monitoring) to deploy advanced monitoring tools that can detect and respond to threats
in real-time.
o RMF Steps: The “Monitor” step is dedicated to continuous monitoring of security controls. This
involves using automated tools to provide real-time insights into the security posture of OT
systems and to detect any anomalies or breaches. [12][14].

2. Real-Time Threat Detection:

o NIST SP 800-53 Controls: Utilize controls such as IR-4 (Incident Handling) and SI-4 (System
Monitoring) to establish real-time threat detection and incident response capabilities.
o RMF Steps: The “Monitor” and “Respond” steps ensure that any detected threats are promptly
addressed and that incident response plans are effectively executed. [12][14].

By leveraging the RMF and NIST SP 800-53 controls, organizations can significantly enhance the
security of their OT systems. This involves a comprehensive approach that includes improving security
hygiene, reducing the attack surface, implementing zero trust practices, and continuous monitoring.
These measures collectively help in mitigating the risks posed by cyberattacks and ensuring the
resilience of critical infrastructure.

Cyber Defense eMagazine – July 2024 Edition 32
Copyright © 2024, Cyber Defense Magazine. All rights reserved worldwide.