Preparing for a DIBCAC High Assessment: Lessons Learned

For contractors in the Defense Industrial Base (DIB), a DIBCAC High assessment is one of the most rigorous tests of cybersecurity maturity you can face. It’s not just a paperwork review—it’s a deep dive into your systems, your processes, and your ability to protect Controlled Unclassified Information (CUI) according to NIST SP 800-171.

We’ve been walking through this process with one of our defense clients, and I want to share what it’s really like to prepare for a DIBCAC High. Whether you’re just starting your compliance journey or you’ve already posted a score in SPRS, these lessons can help you avoid some of the most common pitfalls.

Step 1: Start With an Honest Assessment

The first step is always knowing where you stand. Before we even began preparing for DIBCAC, we conducted a thorough self-assessment against all 110 NIST 800-171 controls.

It’s tempting to give yourself partial credit on controls that are “almost” implemented. But during a DIBCAC assessment, “almost” doesn’t count. We had to be brutally honest about which controls were fully implemented, which had gaps, and which required major investments. This honesty gave us a clear baseline to work from.

👉 Resource: NIST SP 800-171 Rev. 2

Step 2: Build (and Keep Updating) the SSP

The System Security Plan (SSP) became the backbone of our preparation. This document explains how each control is implemented, where data flows, and who is responsible for maintaining security.

We didn’t wait until the end to create it—we built it as we went. Each time we closed a gap or rolled out a new technology, we updated the SSP. By the time the assessment window arrived, our SSP wasn’t a rushed afterthought; it was a living document that reflected reality.

👉 Resource: NIST SSP Guide

Step 3: Tackle the Heavy Lifts Early

Some NIST controls can be closed with policies, procedures, or quick configuration changes. Others require serious planning and time. We learned quickly to focus early on the heavy lifts:

  • Endpoint Detection and Response (EDR/MDR): Traditional antivirus doesn’t cut it. We had to roll out enterprise-grade monitoring and response across every endpoint.

  • SIEM (Security Information and Event Management): Collecting and correlating logs is one thing; tuning a SIEM for meaningful alerts is another. This required both technology and process changes.

  • Data Loss Prevention (DLP): Protecting CUI from leaving the environment—whether by email, Teams, or USB—took extensive planning and tuning.

  • Email security (SPF, DKIM, DMARC, quarantine management): We hardened mail flow to reduce the risk of spoofing and phishing.

  • Privileged Access and MFA: These weren’t just technical changes—they required cultural shifts in how admins worked.

By frontloading these efforts, we avoided last-minute fire drills.

Step 4: Focus on Documentation as Much as Technology

One of the biggest lessons learned? The documentation workload is just as heavy as the technical work. Every control requires evidence: screenshots, logs, policies, training records, meeting minutes, and more.

We made sure to document as we implemented. This way, when DIBCAC assessors ask, “Show us how this control is being enforced,” we’re not scrambling to pull proof—we already have it.

Step 5: Assign Subject Matter Experts (SMEs)

A DIBCAC High isn’t something IT alone can carry. We identified SMEs across departments: IT, HR, compliance, and leadership. Each person was responsible for speaking to the controls in their area.

For example, HR had to be prepared to answer questions about personnel security and training. IT staff had to show how endpoint monitoring and patching were handled. Leadership had to demonstrate buy-in and oversight. This distributed responsibility gave us confidence going into the assessment.

Step 6: Rehearse the Assessment

We didn’t walk in blind. Before the official assessment, we ran internal rehearsals—mock interviews, document reviews, and system walkthroughs. This helped SMEs get comfortable explaining their responsibilities and gave us a chance to tighten up documentation gaps.

Step 7: Understand the DIBCAC Perspective

It’s important to remember that the DIBCAC assessors aren’t looking for perfection—they’re looking for honesty, consistency, and maturity. They want to see that you have a process for maintaining compliance over time, not just a shiny setup right before the audit.

Walking in with a living SSP, clear evidence, and SMEs who can speak confidently to their areas makes a huge difference in how assessors perceive your program.

Step 8: Plan for the Aftermath

A DIBCAC High assessment doesn’t end with the exit brief. You may leave with findings or remediation items. We planned for this reality from the beginning. Having a clear roadmap, active POA&M (Plan of Actions and Milestones), and resources available for remediation ensures that findings don’t stall your compliance journey.

Final Thoughts

Preparing for a DIBCAC High assessment is a massive undertaking. It requires technology upgrades, process changes, cultural shifts, and mountains of documentation. But with the right plan, it’s manageable—and it can actually strengthen your organization’s overall security posture.

At Firethorne, we’ve been through this process alongside defense contractors and know exactly where the pressure points are. From building the SSP to standing up SIEMs to running mock assessments, we know how to get organizations ready for one of the toughest tests in the DIB.

If your organization is staring down a DIBCAC High, don’t go it alone. Reach out to Firethorne, and let’s make sure you walk in prepared and confident.