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Disclaimer: This article was originally published in February 2023 and has since been updated for comprehensiveness and accuracy.
CMMC lines up with NIST by matching Level 2 to the 110 requirements in NIST SP 800-171 Revision 2 and adding outside checks. It becomes mandatory for all DoD contractors by 2028, while NIST 800-171 remains self-assessed.
Several DoD contractors are not familiar with the difference between these frameworks.
Unfortunately, choosing the wrong one can cost you contracts and leave your data exposed to hackers. As a DoD contractor, it’s crucial to stay informed so you don’t miss deadlines that can stop you from getting future work.
Intelligent Technical Solutions (ITS) has over 20 years of experience helping hundreds of businesses with these requirements. With a team that has decades of experience in cybersecurity and compliance, we help DoD contractors get certified and keep their data safe.
In this article, we’ll explore the differences between CMMC and NIST 800-171. With helpful insights from Sean Harris, ITS Chief Security Risk Officer, we’ll find answers to questions like:
After reading, you'll understand which one you need and how to get started with your compliance.
What Is NIST 800-171?
NIST stands for the National Institute of Standards and Technology. They created a set of rules called NIST 800-171. These rules protect sensitive government information on contractor computers.
The government calls this information Controlled Unclassified Information (CUI). Although CUI is not necessarily top-secret information, it still requires protection. Examples of CUI include:
- contract details
- technical data
- business plans
The NIST 800-171 framework has specific security rules that cover things like passwords, system monitoring, and responding to attacks. Federal agencies require contractors to follow these rules when handling CUI.
Here's the key part: NIST 800-171 uses self-assessment. This means contractors check their own work. They grade themselves and report scores to the government.
The downside of this form of assessment lies in problems concerning the honor system. Some issues observed are:
- dishonesty in about security
- lack of proper self-assessment knowledge
- hidden security gaps
Read More: What is NIST 800-171? (& What Does it Mean for Businesses?)
What Is CMMC?
The Department of Defense (DoD) noticed the problem with self-reporting. To address this, they formed the Cybersecurity Maturity Model Certification (CMMC).
Instead of trusting contractors to grade themselves, CMMC requires outside experts to evaluate the work. These assessors verify that security controls actually work.
The DoD published the final CMMC rule in October 2024, which became official in December 2024. With the rollout now occurring in phases through 2028, over 300,000 companies are required to follow these new rules.
Having CMMC credentials, Harris explains: "Any organization that wants to do work with the Department of Defense or any vendor that's doing work for the Department of Defense is going to be subject to CMMC."
CMMC has three levels. Each level matches how sensitive your data is.
- Level 1 protects basic contract information and requires adherence to 17 security practices. You can conduct self-assessments once a year.
- Level 2 protects CUI and needs all 110 controls from NIST 800-171 Revision 2. Most companies at this level need a certified outside expert to check their work. Some conduct self-assessments themselves.
- Level 3 protects the most sensitive programs and needs extra security controls. For this level, the government checks your work directly.
How Does CMMC Differ from NIST 800-171?
Both frameworks protect government data and set up security rules. Their main differences involve answering three key questions:
Is It Mandatory?
NIST 800-171 works on the honor system. You check yourself. You report your score if you want to. Nobody verifies your work in most cases.
On the other hand, CMMC is required for all DoD contractors. The rollout began in December 2024, and all levels will be fully in place by 2028, so your DoD contract may already require CMMC depending on the level you need.
Without this certification, you won’t be allowed to have contracts or bid on new work. You also can't keep doing your current work after the rules take effect.
Harris warns about the consequences: "The False Claims Act applies. If a company is found to be non-compliant with CMMC requirements and still claims compliance to obtain government contracts or payments, they may be subject to FCA enforcement."
The False Claims Act is a federal law. It punishes people who lie to get government money. Breaking this law leads to hefty fines and legal trouble.
Does It Use a Maturity Model?
A maturity model uses levels to show how advanced your security is.
NIST SP 800-171 does not use a maturity model. It gives a baseline of 110 controls for any contractor that handles CUI.
On the other hand, CMMC uses a maturity model with three levels. Your contract sets the level based on data sensitivity. Basic work needs basic protection, while more advanced work needs stronger security.
Does It Require a Third-Party Assessor?
NIST 800-171 lets you evaluate yourself. However, this framework created problems. Some companies exaggerate their security, while others lack an understanding of the requirements to assess correctly.
CMMC requires outside experts at Levels 2 and 3. These experts are called C3PAOs (Certified Third-Party Assessment Organizations). C3PAOs have undergone special training and authorization, enabling them to conduct comprehensive checks.
Their assessment process includes:
- policy reviews
- procedure evaluation
- security tools tests
- staff interviews
In terms of the investment, Harris explains: "The cost of certification through a C3PAO can range between $30,000 to $100,000 every three years. Failing means not only losing that investment but also delaying your ability to work with the DoD."
Once you pass every step in the evaluation process, you’ll receive certification.
Need Help with CMMC or NIST Compliance?
CMMC builds on top of NIST 800-171. It doesn't replace it. Instead, CMMC adds verification to make sure the rules work.
Here are the key differences to remember:
- CMMC is mandatory when fully rolled out. You must have it to work with the DoD.
- You need the right maturity level. The level depends on the data you handle.
- You need an audit from a certified outside organization. This proves that you really meet the requirements.
At ITS, we understand compliance can feel overwhelming. You need to meet several requirements and prepare for rigorous assessments. The certification process also requires you to implement complex security controls.
With decades of experience supporting businesses through certification, ITS is equipped with the necessary expertise to help you rise above these challenges.
Ready to kickstart your success in CMMC compliance? Schedule a meeting with our experts to learn how we can help you reach your compliance goals.
You can also download our eBook for more details on CMMC compliance.
Learn more about staying compliant with these free resources in our Learning Center:
- What Types of Businesses Need CMMC Compliance?
- What CMMC Level Do I Need? A Step-by-Step Guide
- CMMC Assessment vs. CMMC Audit: What's the Difference?
Frequently Asked Questions
Q: What is the main difference between CMMC and NIST 800-171?
A: CMMC is required for DoD contractors and outside experts to verify your security compliance. NIST 800-171 lets you conduct a self-assessment.
Q: Do I need both CMMC and NIST 800-171 compliance?
A: CMMC Level 2 includes all NIST 800-171 requirements. When you get CMMC Level 2 certification, you also prove that you meet NIST 800-171 standards.
Q: When does CMMC become mandatory for DoD contracts?
A: CMMC Phase 1 implementation of self-assessments are to begin on November 10, 2025. All DoD contracts will require CMMC certification by 2028.
Q: How long does CMMC certification take?
A: Most companies need 12 to 18 months for Level 2. The duration depends on your current security setup and the amount of money you can invest.
Q: Can small businesses afford CMMC compliance?
A: Yes, many small businesses get compliant with good planning and expert help. Although certification costs money, losing DoD contracts costs more.
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