NIST 800-171 Compliance: A Complete Guide

The National Institute of Standards and Technology (NIST) is a federal agency focused on ensuring sensitive data is handled appropriately by government contractors and security providers.

For defense contractors, NIST 800-171 focuses on Controlled Unclassified Information (CUI) is handled.

If you’re prepping for a NIST assessment or just trying to learn more about compliance, this guide is for you We’ll share what exactly NIST SP 800-171 is, why contractors in the Defense Industrial Base (DIB) need to comply and how frameworks like DFARS and CMMC fit into the bigger government cybersecurity picture.

What Is NIST SP 800-171

NIST SP 800-171 details how Department of Defense (DoD) contractors must protect CUI when working with the U.S. government.

Controlled Unclassified Information (CUI) is sensitive but unclassified data like engineering drawings, contract details, manufacturing specs, or logistics data. It’s information that isn’t top secret but could still harm national interests if leaked. That’s why the NIST security requirements exist.

The NIST standard originates from the Federal Information Security Modernization Act (FISMA) and is codified under DFARS 252.204-7012 for defense contractors. NIST SP 800-171 sets the baseline controls for safeguarding that information in non-federal systems.

But the goal of NIST isn’t just to prove your information systems handle data correctly, meeting the requirements shows your business can be trusted to handle sensitive information as part of defense contracts.  

Who Needs to Comply

If you handle CUI, even indirectly, NIST 800-171 applies to your business. That icnludes:

• Prime contractors and subcontractors in the DoD supply chain
• Manufacturers and logistics providers handling defense data
• SaaS vendors or MSPs serving federal contractors
• Universities and research institutions with government grants

The key enforcement mechanism is the DFARS clause 252.204-7012, which flows down through every subcontract.

If you’re part of a defense supply chain, compliance isn’t optional. To achieve Cybersecurity Maturity Model Certification (CMMC) Level 2 (needed if you handle CUI), organizations need to past a third-party assessment with a C3PAO. Which is why now is the time to start building your foundation.

NIST 800-171 Controls

The NIST framework organizes its 110 controls into 17 control families. Families are essentially buckets of related practices. Here’s a breakdown of each control family:

1. Access Control (AC): Ensures your business restricts data access to people who strictly need to use it. Contractors must use role-based permissions and require multi-factor authentication for all admin or privileged accounts.
2. Awareness and Training (AT): Makes sure your employees are trained on cybersecurity risks and responsibilities.
3. Audit and Accountability (AU): Means your business must establish logs and monitoring for all user and system activity.
4. Configuration Management (CM): Ensures your organization maintains secure configurations.
5. Identification and Authentication (IA): Means all users have to verify their identity before they can access CUI.
6. Incident Response (IR): A written plan that explains exactly how your business responds to a cyber incident.
7. Maintenance (MA): Systems for handling maintenance and updates, ensuring security at all times.
8. Media Protection (MP): Safeguard all devices so data stays protected if they are lost.
9. Personnel Security (PS): A screening process for all new hires with background checks before granting system access.
10. Physical Protection (PE): Ensures physical access to your building and is secure with  badge-controlled doors and detailed visitor logs.
11. Risk Assessment (RA): Regular penetration testing and audits to identify any risks to your IT systems.
12. Security Assessment (CA): Regular assessments of your security controls to ensure it’s all working as it should be.
13. System and Communications Protection (SC): Use encrypted communication to ensure communications channels are secure.
14. System and Information Integrity (SI): Constantly be detecting new potential vulnerabilities.

How to Achieve NIST 800-171 Compliance

To verify your organization meets NIST 800-171, you’ll need to perform a self-assessment. Though if your business is pursuing CMMC Level 2, you’ll need to pass an assessment from a C3PAO.

Here are the steps your organization should take to achieve NIST 800-171 compliance:

1. Scoping: Study the NIST 800-171 requirements and figure out exactly which of your systems touch Controlled Unclassified Information (CUI) lives in your systems. At this stage, you’ll want to work through the 14 families listed above and the 110 controls within NIST 800-171 to figure out what needs to be done to ensure compliance.
2. Gap Analysis: Now you’ve figured out where your organization is starting from, it’s time to see where the gaps are between your current security posture and what’s needed to comply with NIST 800-171.
3. Documentation: Make sure to document any control gaps and create and maintain your System Security Plan (SSP). These documents explain how you meet each control and what’s still being improved. Keep them up to date with evidence, screenshots, and notes from your implementation work.
4. Conduct a Self-Assessment: If you’re focused on NIST 800-171 rather than CMMC Level 2, you can complete a self-assessment based on NIST SP 800-171A. Post-assessment, submit your Supplier Performance Risk System (SPRS) score and if you have any gaps to fill after the assessment, create a Plan of Action and Milestones (POA&M)

If your organization isn’t super familiar with cyberseucrty frameworks like NIST and CMMC, onboarding a parter like Workstreet could help your business to achieve NIST 800-171 compliance in a timely manner without the headaches.

If you’re focusing on NIST 800-171 with a view to completing CMMC Level 2 (which will soon be mandatory for DoD contractors that handle CUI, we recommend working with a CMMC RPO to guide your business through the process.

NIST Compliance Costs, Timelines, and Common Pitfalls

From start to finish, full NIST 800-171 compliance can take 12-18 months — though sometimes it may be faster if your security posture is mature and already closely aligned with the NIST 800-171 compliance controls.

But this lengthy timelines is exacty why businesses who work with the DoD need to get moving ASAP. The CMMC final rule has now been signed and deadlines are coming up fast — and if your business doesn’t have the relevant CMMC level by the deadline, your eligibility for government contracts by be gone.

Where Organizations Go Wrong

At Workstreet, we’ve worked with a number of organizations working towards NIST and CMMC compliance, here’s where we often see them go wrong:

• Over-scoping: A key part of the scoping process is defining your system boundary and creating a CUI enclave to save having to audity your entire IT infrastructure.
• Neglecting continuous monitoring: Compliance doesn’t stop after the audit. Controls need ongoing tracking, log reviews, and periodic testing to remain valid.
• Ignoring the supply chain: If you’re a DoD prime contractor, you’re also resposible for ensuring any sub-contractors or third-party providers your business works with also meet the needed NIST or CMMC requirements.

NIST vs. CMMC

Although NIST 800-171 and CMMC share the same foundation, they serve different purposes.

CMMC is built directly on top of NIST 800-171's foundation, however NIST relies on self-attestation, while CMMC Level 2 requires a more in-depth collection of documentation and proof as well as approval from a third-party assessor.

NIST 800-171 is required under DFARS for contractors handling CUI, but compliance is based on self-assessments. CMMC, on the other hand, ties compliance directly to contract eligibility. Starting in late 2025, if a government contract requires a certain CMMC level and you don’t have it, you cannot bid for or win that DoD contract.

Learn more about NIST vs. CMMC here.

Final Thoughts

NIST 800-171 is about proving that your organization handles sensitive government data in the correct manner. If you meet NIST 800-171 or CMMC Level 2 requirements for handling CUI, it’s a sign your business can be trusted.

you can be trusted with government data. Done right, it becomes a signal of maturity and

If you’re ready to streamline NIST 800-171 compliance and prepare for CMMC certification, Workstreet is the only AI-powered CMMC RPO and can guide you every step of the way. Book a meeting with one of our compliance experts today.