Common CMMC Mistakes: Poor Assessment Preparation

Top 15 Most Common CMMC Compliance Mistakes Series #7

This article is part of our expert-led series: The Top 15 Most Common CMMC Compliance Mistakes (and How to Solve Them). Throughout this series, we're dissecting the frequent errors, misunderstandings, and misconceptions organizations encounter on their path to CMMC certification, drawing insights from seasoned CCPs, CISOs, and CCAs.

Today’s focus:  We explore the critical aspects of assessment preparation and how to avoid common mistakes.

What You’ll Learn

• Why preparation is more than just filling out documentation
• The key components auditors are really looking for
• The role of tabletop exercises, leadership sign-off, and risk assessments
• Best practices for getting your team ready to succeed
  
  

CMMC Assessments Are Not a Performance, So Don’t Script One

Too many organizations treat CMMC assessments like a presentation or scripted interview. But assessors don’t want to hear rehearsed answers. They want to see real-world evidence that your organization is operating securely each and every day.

Key mistake areas include:

• Over-rehearsing answers: Auditors don’t want memorized scripts. Just like in court, your team should answer the question asked and nothing more. Clarity, not volume, builds trust.
  
  
• Uninformed personnel: Key staff members are often unaware of their responsibilities during an audit or can’t explain what they do in a security context.
  
  
• Lack of situational readiness: When asked what they’d do in the event of a breach, many teams stumble. This reflects a lack of internal coordination and real-world preparedness.

Documentation Tells a Story. It Needs to be True and Will be Tested

Your System Security Plan (SSP) should read like a narrative that explains how your business manages and secures its information systems. It should match what’s happening in reality, not what you think auditors want to see.

To pass an assessment with confidence, organizations must have:

• Documented Policies, Plans, and Procedures for each CMMC objective
  
  
• Clear ownership of tasks and responsibilities
  
  
• Evidence that these documents are regularly reviewed and updated
  

When an SSP doesn’t align with actual operations, auditors will notice. Discrepancies are a red flag.

The Risk You Overlook: Internal Security Risk Assessments

Most companies underestimate the importance of conducting formal internal security risk assessments. These aren’t just a best practice, they’re a requirement.

Risk assessments should be:

• Conducted at least annually
  
  
• Used to identify gaps and assign mitigation strategies
  
  
• Led or overseen by someone with cybersecurity expertise
  
  
• Shared with leadership and incorporated into broader strategy

If your organization has never completed one, it’s a major sign you’re not ready for a full CMMC assessment.

Tabletop Exercises and Leadership Involvement

A tabletop exercise is a simulation, it's your team’s chance to practice what they would do in the event of a breach, outage, or incident. Too often, these are skipped or siloed within IT. That’s a problem.

To be CMMC-ready, you must:

• Conduct tabletop exercises annually at minimum
  
  
• Involve key personnel outside of IT (HR, operations, legal, leadership)
  
  
• Ensure executive sign-off on your security program, policies, and risk mitigation plans
  
  

Assessors are looking for leadership support and operational maturity. If the people at the top aren’t engaged, it shows.

In Summary: An Assessment is an Investigation, not a Show.

Assessment readiness is more than having the right paperwork. It’s about knowing your system, engaging your people, and being ready to demonstrate how security is actually lived out inside your business.

With the right preparation, your CMMC assessment won’t feel like a performance, it will feel like validation.

Key Takeaways

• CMMC assessments require operational and cultural readiness, not just documentation
• SSPs, policies, and procedures must be current and reflect real practices
• Annual risk assessments and tabletop exercises are essential
• Leadership must actively support and sign off on your cybersecurity program

Up Next In Our Top 15 Most Common CMMC Mistakes Series:

In our next article, we'll review how failing to secure executive support and adequately plan for the financial and resource commitments of CMMC compliance can derail your certification efforts.