Understanding CUI Enclaves

Companies working with the Department of Defense and government agencies are using security-first solutions to make their operations more efficient and comply with rules.  For organizations dealing with Controlled Unclassified Information (CUI), the establishment of secure environments known as CUI Enclaves is a critical component in fortifying data security. This guide delves into the significance of CUI enclaves, their role in data protection, and why they have become popular with companies in the defense industrial base looking to comply with NIST 800-171 and pending CMMC regulations. 

What are CUI Enclaves? 

CUI Enclaves are stand-alone, secure spaces designed to house and manage Controlled Unclassified Information.  From the CMMC Assessment Process (CAP), “[An Enclave is] a set of system resources that operate within the same security domain and that share the protection of a single, common, and continuous security perimeter.  A segmentation of an organization’s network or data that is intended to “wall off” that network or database from all other networks or systems (1).”  These CUI Enclaves may also help to limit the footprint of CUI data on the organization and help reduce the exposure of CUI data to the rest of the enterprise systems, helping keep the unnecessary organizational systems out of scope.  

CUI and the DoD

From the Defense Counterintelligence and Security Agency (DCSA), they state, “Safeguarding classified and sensitive information is one of the most critical ways to maintain our national security.  CUI is an overarching term representing many different categories, each authorized by one or more laws, regulations, or government-wide policies.  Because there are fewer controls over CUI as compared to classified information, CUI is an attractive target for adversaries (2).”  CUI Enclaves play a pivotal role in aligning with DoD standards, providing a secure foundation for organizations to operate within the guidelines set forth by one of the most stringent regulatory bodies and can help an Organization Seeking Certification (OSC) achieve this standard.

Understanding a Basic Enclave Architecture

 At the core of the enclave concept is the effort to fortify a particular class of data security, in this case CUI, while allowing other organizational security practices and principles to remain in place within the organization but outside the enclave.  The principles outlined in the enclave architecture prioritize security and compliance, drawing from key characteristics such as isolation from host networks, stringent user authentication, and restricted access to authorized information.

1. Isolation from Host Networks:

The CUI Enclave’s architecture ensures a strict segregation from host networks. This isolation is a pivotal security measure, preventing unauthorized entities from infiltrating the enclave and safeguarding the integrity of sensitive information. The physical and/or logical separation minimizes the risk of external threats compromising the enclave’s security.

2. Limited Access to Authorized Information:

Most commercial enclave solutions are built on the principle of least privilege, allowing access only to those individuals who require specific information for their designated roles. This restricted access minimizes the surface area for potential security breaches and ensures that sensitive data is accessible solely to those with a legitimate need. It aligns with the overarching goal of maintaining confidentiality and preventing unauthorized disclosure.

3. Cryptographic controls:

Encrypting the information in the enclave, both at rest and in transit, adds a layer of security to protect the information if the enclave were to be breached by unauthorized access. This is also a common feature of most commercially available enclave solutions.

4. Auditing Control and Monitoring:

All access and activity to the enclave should be logged and monitored.  This adds a layer of oversight and the ability to provide forensics in the case of malicious or any other security incidents.

Common Pitfalls of a CUI Enclave:

  • Not a silver bullet:  CUI Enclaves in and of themselves must be configured correctly and even after doing so, will not cover all the controls needed.  Most solutions, if not all, only support the fulfillment of a control or set of controls and is not sufficient or adequate without end-user support and action.  The integration processes will need to be documented, end-users will need to be trained, and these steps are generally not going to be provided by the enclave solution.
  • Too much business is defense work:  If most of your business is tied to the federal government, it may not make sense to carve out a smaller space.  An enclave will end up causing more work to grow the space instead of considering your enterprise environment as your boundary.
  • One-Stop-Shop:  Some companies claim they have an enclave that you can simply pay a fee and put your data there to be compliant.  Be wary and fully vet any such claims.  Some companies only do a very small portion that may potentially meet requirements and even then, they may not be qualified to do.  If you see claims that someone is a one-stop-shop, head in the other direction.
  • Shared Responsibility Matrix (SRM):  Make sure that you ask for this when hosting an enclave outside of your control.  Ask the provider to give you an SRM and what controls their solution fully addresses, verify any claims on what is being fully inherited.    Any control that is marked as partially inherited means you have some work to do.
  • Location, Location, Location:  Where is your data being hosted?  If you have ITAR export control requirements, knowing where your data is being hosted is critical.  Also knowing who has access to your data.  Ensuring that only US persons, including support staff don’t lead to a non-compliance issue.  FedRAMP Moderate compliant or equivalent is also a requirement for any cloud service provider.  If your chosen hosting provider doesn’t meet this requirement, it could be an automatic failure.

Benefits of a CUI Enclave

While CUI Enclaves will not be a perfect solution for everyone, as a quick way to isolate data in smaller or less complex environments where DoD work is well defined and separate from other client work, they may provide some benefits, including the following:

  • Enhanced Security: CUI Enclaves can provide a heightened level of security, safeguarding sensitive information from potential breaches if the data can be well defined.
  • Compliance Assurance: Many enclave solutions are purpose built and as such, they may support organizations in their efforts to comply with regulatory frameworks and industry standards.
  • Risk Mitigation: Enclaves can support quick implementation of controls in support of efforts to mitigate risks associated with unauthorized access and data compromise.
  • Confidentiality: The greatest strength of most enclave solutions is that most are purpose built to ensure that sensitive information is kept confidential within the enclave, limiting exposure to external threats.

Why Enclaves Have Become Popular

To ensure compliance with the CMMC framework, defense contractors must implement a dynamic range of cybersecurity measures. CUI Enclaves have emerged as one data management solution to support CMMC compliance efforts.  They have helped some organizations with reducing the burden of attempting to make their entire corporate network become compliant but again, enclaves are not one size fits all nor are the appropriate for every organization with compliance requirements.

If you would like to discuss enclaves in greater detail with one of our compliance experts, reach out to us today.


  1. CMMC Assessment Process (CAP) DRAFT v5.6.1