CMMC v2.11 Practices


Reference: CMMC v2.11

Family: SC

Level Introduced: 2

Title: Data at Rest

Protect the confidentiality of CUI at rest.

Further Discussion:
CUI at rest means information that is not moving through the network; typically this means data currently stored on hard drives, media, and mobile devices. Implement the necessary security controls to protect the confidentiality of CUI at rest. Although an approved encryption method protects data stored at rest, there are other technical and physical solutions. The methods chosen should depend on the environment and business needs.

Implementing encryption for CUI is one approach to this requirement, but it is not mandatory. Physical security is often employed to restrict access to CUI, particularly when it resides on servers within a company’s offices. Other approaches for protecting CUI include system-related protections such as configurations and rule sets for firewalls, gateways, intrusion detection/prevention systems, filtering routers, and authenticator content that eliminate attempts at exfiltration. You may also employ other security requirements including secure off-line storage.

Because the use of cryptography in this requirement is to protect the confidentiality of CUI, the cryptography used must meet the criteria specified in requirement SC.L2-3.13.11.

This requirement, SC.L2-3.13.16, specifies confidentially be provided for CUI at rest and complements MP.L2-3.8.9, which specifies confidentially of CUI at backup storage locations. This requirement, SC.L2-3.13.16, also leverages SC.L2-3.13.11, which specifies that the algorithms used must be FIPS-validated cryptography.

Example 1
Your company has a policy stating CUI must be protected at rest and you work to enforce that policy. You research Full Disk Encryption (FDE) products that meet the FIPS encryption requirement. After testing, you deploy the encryption to all computers to protect CUI at rest [a].

Example 2
You have used encryption to protect the CUI on most of the computers at your company, but you have some devices that do not support encryption. You create a policy requiring these devices to be signed out when needed, stay in possession of the signer when checked out, and to be signed back in and locked up in a secured closet when the user is done with the device [a]. At the end of the day each Friday, you audit the sign-out sheet and make sure all devices are returned to the closet.

Potential Assessment Considerations
• Is the confidentiality of CUI at rest protected using encryption of storage devices and/or appropriate physical methods [a]?

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Source: CMMC v2.11