Zero Trust Cybersecurity for Defense: A Practical Guide for DoD Networks

Zero trust is no longer optional for defense networks. Executive Order 14028, the DoD Zero Trust Strategy, and CISA’s Zero Trust Maturity Model have made it clear: every federal agency and defense contractor must move beyond perimeter-based security. But implementing zero trust in classified defense environments presents challenges that generic enterprise frameworks don’t address.

At Zapata Technology, we implement cybersecurity solutions across classified DoD networks, including work as the prime contractor on the MCTSSA NETC IDIQ for Marine Corps C4I cybersecurity. Here’s our perspective on making zero trust work in defense environments.

What Zero Trust Means for Defense Networks

The core principle of zero trust — “never trust, always verify” — sounds simple. In practice, it requires fundamental changes to how defense networks are architected, monitored, and managed:

• Identity-centric security — Every user, device, and service must be continuously authenticated and authorized, regardless of network location. PKI/CAC authentication is a starting point, not the finish line.
• Micro-segmentation — Network segments must be isolated so that compromise of one segment doesn’t enable lateral movement. This is especially critical in multi-classification environments.
• Continuous monitoring — Real-time visibility into every network transaction, with automated detection and response capabilities. Traditional periodic scanning is insufficient.
• Least privilege access — Users and services should have only the minimum access required to perform their function, with access decisions made dynamically based on context.
• Data-centric protection — Encrypt data at rest and in transit, with access controls tied to data sensitivity and user authorization, not just network location.

The Defense-Specific Challenge

Most zero trust frameworks and vendor solutions are designed for enterprise IT environments with cloud connectivity, modern identity providers, and relatively homogeneous technology stacks. Defense networks are different:

Legacy Systems Integration

Defense networks run systems that predate zero trust by decades. Weapons systems, C4ISR platforms, and operational technology often cannot be upgraded or replaced. Zero trust implementations must wrap these legacy systems with modern security controls without breaking operational capability.

Multi-Classification Environments

Defense organizations operate across multiple classification levels simultaneously. Zero trust architectures must enforce strict separation between classification levels while enabling authorized cross-domain information sharing. This adds complexity that commercial zero trust frameworks don’t address.

Disconnected and Tactical Operations

Zero trust assumes continuous connectivity to identity providers and policy engines. Tactical environments may be disconnected, bandwidth-constrained, or under active adversary interference. Zero trust implementations must support degraded operations with pre-provisioned policies and local authentication capabilities.

RMF and Accreditation

Every zero trust component deployed on a DoD network requires Risk Management Framework (RMF) accreditation. This means detailed security control documentation, assessment, and Authority to Operate (ATO) approvals. The accreditation burden can slow zero trust adoption significantly if not planned for from the start.

A Practical Implementation Roadmap

Based on our experience implementing cybersecurity solutions across DoD networks, we recommend a phased approach:

1. Assess the current state against the DoD Zero Trust Reference Architecture and CISA’s maturity model. Identify the highest-risk gaps and the quick wins.
2. Strengthen identity and access management first. This is the foundation everything else builds on. Implement multi-factor authentication, conditional access policies, and privileged access management.
3. Deploy network monitoring and visibility tools for continuous monitoring. You can’t secure what you can’t see. Our continuous monitoring work on MCTSSA programs has demonstrated the value of real-time network visibility.
4. Implement micro-segmentation starting with the highest-value assets and most sensitive data enclaves. Expand incrementally based on risk assessment.
5. Automate security response with SOAR (Security Orchestration, Automation, and Response) capabilities. Human-only incident response can’t keep pace with modern threats.

CMMC and the Compliance Imperative

The Cybersecurity Maturity Model Certification (CMMC) program adds another dimension to the cybersecurity challenge for defense contractors. CMMC Level 2 aligns with NIST 800-171 Rev. 2, requiring 110 security practices for handling Controlled Unclassified Information (CUI). Zapata Technology maintains NIST 800-171 compliance and is positioned for CMMC certification, ensuring our systems and processes meet the standards required to handle sensitive defense information.

For defense contractors who haven’t started their CMMC journey, the time to act is now. The rulemaking process is advancing, and organizations that wait for final rules will face compressed timelines and increased costs.