CMMC Practice SC.L2-3.13.16 – Data at Rest: Protect the confidentiality of CUI at rest.
Links to Publicly Available Resources
Discussion [NIST SP 800-171 R2]
Information at rest refers to the state of information when it is not in process or in transit and is located on storage devices as specific components of systems. The focus of protection at rest is not on the type of storage device or the frequency of access but rather the state of the information. Organizations can use different mechanisms to achieve confidentiality protections, including the use of cryptographic mechanisms and file share scanning. Organizations may also use other controls including secure off-line storage in lieu of online storage when adequate protection of information at rest cannot otherwise be achieved or continuous monitoring to identify malicious code at rest.
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 practice, 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.
This practice, SC.L2-3.13.16, requires confidentially be provided for CUI at rest and complements MP.L2-3.8.9, which requires confidentially of CUI at backup storage locations. This practice, SC.L2-3.13.16, also leverages SC.L2-3.13.11, which specifies that the algorithms used must be FIPS-validated.