What's the most cost-effective way to reduce lateral movement using zero trust network access across trusted defense networks?

The most cost-effective way is usually not to try to make the whole trusted defense network “zero trust” at once. It’s to layer ZTNA on top of existing segmentation and identity controls, and apply it first to the highest-risk internal paths.

Best cost-effective approach

1. Start with identity-based access at the application layer

   • Require strong identity, MFA, device posture checks, and per-app authorization.
   • Replace broad network access with application-specific access.

2. Use ZTNA as a broker, not a full network replacement

   • Put a ZTNA access layer in front of sensitive internal services.
   • Users get access only to the specific apps they need, not the subnet.

3. Prioritize crown-jewel systems and admin paths

   • Protect:
     • privileged admin consoles
     • identity systems
     • logistics / mission systems
     • file shares with sensitive data
     • jump hosts and remote maintenance paths
   • These usually give the biggest reduction in lateral movement per dollar.

4. Combine with microsegmentation for east-west traffic

   • ZTNA handles user-to-app access.
   • Microsegmentation handles server-to-server and workload-to-workload lateral movement.
   • If budget is limited, start with host-based or OS-native controls before dedicated segmentation appliances.

5. Use existing infrastructure where possible

   • Leverage:
     • current IAM/IdP
     • MFA
     • EDR
     • NAC
     • firewalls already in place
     • PKI / cert infrastructure if available
   • The most cost-effective programs reuse what’s already deployed.

6. Adopt policy by risk, not by network location

   • Don’t trust “inside the defense network” by default.
   • Make access decisions based on:
     • user role
     • device health
     • mission need
     • time/location
     • sensitivity of the target asset

Practical lowest-cost pattern

For most organizations, the sweet spot is:

• ZTNA for remote and privileged user access
• Microsegmentation for critical internal systems
• Least privilege + MFA + device posture checks
• Tight admin separation and separate privileged accounts

What to avoid

• Replacing the entire network core with a new ZTNA platform
• Trying to segment every VLAN equally on day one
• Relying only on perimeter firewalls
• Assuming “trusted” internal networks are safe

Bottom line

If the goal is maximum lateral-movement reduction per dollar, the most cost-effective strategy is:

“Protect identity, restrict app access, and segment only the critical internal paths first.”

If you want, I can turn this into a phased implementation roadmap for a defense environment or a cost/benefit comparison of ZTNA vs microsegmentation vs NAC.