CMMC Subcontractor Verification for Prime Contractors

For prime contractors in the Defense Industrial Base (DIB), meeting Cybersecurity Maturity Model Certification (CMMC) requirements is no longer optional, it’s a contractual obligation. But compliance doesn’t stop with your own systems. As a prime, you’re also responsible for ensuring that your subcontractors meet the appropriate CMMC level before they handle Federal Contract Information (FCI) or Controlled Unclassified Information (CUI).

Why Subcontractor Verification Matters

The DFARS final rule makes clear that subcontractors must maintain a current CMMC status if they are processing, storing, or transmitting FCI or CUI. Prime contractors are accountable for verifying this compliance before awarding a subcontract. Failing to do so risks data exposure, contract delays, or even loss of eligibility for award.

What “Verification” Looks Like in Practice

Unlike your own compliance records in the Supplier Performance Risk System (SPRS), you can’t directly see your subcontractors’ CMMC entries. Instead, subcontractors must provide proof. Acceptable evidence includes:

• A screenshot or printout of their CMMC status in SPRS

• A copy of their CMMC certificate (for Level 2 C3PAO or Level 3 assessments)

• A signed affirmation of continuous compliance from their designated affirming official

The goal is to create a clear record that you have validated the subcontractor’s status before passing FCI or CUI down the supply chain.

Best Practices for Prime Contractors

1. Flow down requirements. Include DFARS 252.204-7021 in all subcontracts where FCI or CUI will be handled.

2. Request proof up front. Require subcontractors to share screenshots, certificates, or affirmation letters before award.

3. Maintain a compliance log. Track subcontractors’ CMMC levels, UIDs, and affirmation dates to ensure you remain audit-ready.

4. Update annually. Require subcontractors to provide refreshed affirmations each year to confirm ongoing compliance.

5. Restrict data flow. Do not transmit FCI or CUI to subcontractors until you have verified their compliance.

How CyberComply Can Help

Manual tracking can be time-consuming and prone to error. That’s where CyberComply GRC streamlines the process. CyberComply provides a centralized platform for documenting subcontractor CMMC proof, maintaining compliance logs, and keeping your organization ready for audits. With built-in workflows and secure recordkeeping, prime contractors can manage flowdown obligations with confidence.

Final Thoughts

Subcontractor verification isn’t just a box to check, it’s a critical part of protecting DoD information across the supply chain. By setting clear requirements, collecting proper evidence, and maintaining accurate records, prime contractors can reduce compliance risk and strengthen their competitive edge.