In today’s defense contracting landscape, cybersecurity is no longer optional—it's mandatory. The U.S. Department of Defense (DoD) introduced the Cybersecurity Maturity Model Certification (CMMC) to ensure that contractors and their entire supply chains implement and maintain strong cybersecurity practices.

However, even if your internal systems are well-protected, your cybersecurity posture can be compromised by one overlooked area: third-party vendors. Choosing the right vendors isn’t just about cost and convenience anymore—it’s about compliance, security, and protecting sensitive government data.

The Supply Chain Reality: Why Third-Party Risk Is a Major CMMC Concern

CMMC applies to the entire Defense Industrial Base (DIB), including subcontractors, cloud service providers, software vendors, and managed service providers (MSPs). Any vendor that processes, stores, or transmits Controlled Unclassified Information (CUI) on your behalf can make or break your compliance standing.

Key Risks from Third Parties:

• Data Breaches: A single breach at a subcontractor’s facility can expose your CUI.
  
  

• Noncompliance: If vendors fail to meet basic CMMC or NIST 800-171 requirements, your organization could lose current or future DoD contracts.
  
  

• Audit Failure: CMMC auditors will assess not only your internal controls but also how you manage vendor relationships.
  
  

• Operational Disruption: Cyber incidents at a critical supplier can lead to downtime, data loss, or delays in delivery.
  
  

What CMMC Says About Vendor Oversight

CMMC requires organizations to:

• Document all external service providers.
  
  

• Understand the scope of vendor access to CUI.
  
  

• Ensure vendors follow proper security controls.
  
  

• Respond appropriately to incidents involving third-party systems.
  
  

Specifically, practices under Access Control (AC), Risk Management (RM), and System and Communications Protection (SC) directly relate to third-party management. For example:

• AC.1.001 – Limit access to authorized users.
  
  

• RM.2.142 – Assess security risks associated with external service providers.
  
  

• SC.3.192 – Separate user functionality from system management functionality.
  
  

How to Choose the Right Vendors for CMMC Compliance

Choosing vendors with poor security can put your CMMC compliance and government contracts at risk. Here’s how to evaluate third-party partners effectively:

1. Assess Security Posture Before You Sign

• Ask about the vendor’s cybersecurity policies.
  
  

• Verify if they follow NIST SP 800-171 or have CMMC Level 1 or 2 preparedness.
  
  

• Request documentation: incident response plans, access controls, encryption practices, and training programs.
  
  

 2. Use Contracts to Set Expectations

• Include cybersecurity clauses that align with CMMC requirements.
  
  

• Define responsibilities around:
  
  

• Data protection
  
  

• Breach notification (typically within 72 hours)
  
  

• Right to audit or request compliance evidence
  
  

• Termination for security failure or noncompliance
  
  

3. Monitor and Reassess

• Set a regular schedule for vendor reviews.
  
  

• Track security incidents or changes in compliance status.
  
  

• Require updated certifications or evidence of ongoing compliance efforts.
  
  

4. Classify Vendor Risk Levels

• Not all vendors present equal risk. Use a tiered risk management approach:
  
  

• High-risk: Direct access to CUI or your internal systems
  
  

• Medium-risk: Indirect access or access to business-critical operations
  
  

• Low-risk: No access to sensitive data
  
  

 5. Establish a Vendor Management Program

• Document vendor inventory, risk ratings, compliance status, and points of contact.
  
  

• Integrate vendor risk management into your overall cybersecurity strategy.
  
  

Case in Point: SolarWinds & Supply Chain Breaches

The 2020 SolarWinds cyberattack demonstrated how attackers exploit third-party software providers to infiltrate hundreds of organizations, including U.S. federal agencies. This breach underscored the importance of knowing exactly who has access to your systems and how secure their environment really is.

How Techellence Helps Secure Your Vendor Relationships

At Techellence, we help government contractors and suppliers:

• Identify and assess risky third-party vendors
  
  

• Build compliant vendor contracts with proper cybersecurity clauses
  
  

• Implement third-party monitoring frameworks
  
  

• Prepare for CMMC audits with full supply chain visibility
  
  

We know that navigating compliance and vendor security is complex—but you don’t have to do it alone.

Key Takeaways

• Your CMMC compliance depends on your vendors. Treat their cybersecurity as seriously as your own.
  
  

• Do your due diligence. Vet vendors carefully, contract correctly, document everything, and update regularly.
  
  

• Work with trusted advisors. Techellence offers expert guidance to help you manage vendors, meet CMMC requirements, and reduce risk.