DISCUSSION [NIST SP 800-171 R2]
Cryptographic standards include FIPS-validated cryptography and NSA-approved cryptography
Further Discussion
A remote access session involves logging into the organization’s systems such as its internal network or a cloud service provider from a remote location such as home or an alternate work site. This remote access session must be secured using FIPS-validated cryptography to provide confidentiality and prevent anyone from deciphering session information exchanges.
When CMMC requires cryptography, it is to protect the confidentiality of CUI. FIPS-validated cryptography means the cryptographic module has to have been tested and validated to meet FIPS 140-1 or -2 requirements. Simply using an approved algorithm is not sufficient – the module (software and/or hardware) used to implement the algorithm must be separately validated under FIPS 140. Accordingly, FIPS-validated cryptography is required to meet CMMC practices that protect CUI when transmitted or stored outside the protected environment of the covered contractor information system (including wireless/remote access). Encryption used for other purposes, such as within applications or devices within the protected environment of the covered contractor information system, would not need to be FIPS-validated. This practice, AC.L2-3.1.13, requires the use of cryptographic mechanisms when enabling remote sessions and complements five other practices dealing with remote access (AC.L2-3.1.12, AC.L2-3.1.14, AC.L2-3.1.15, IA.L2-3.5.3, and MA.L2-3.7.5):
AC.L2-3.1.12 requires the control of remote access sessions.
AC.L2-3.1.14 limits remote access to specific access control points.
AC.L2-3.1.15 requires authorization for privileged commands executed during a remote session.
IA.L2-3.5.3 requires multifactor authentication for network access to non-privileged accounts.
Finally, MA.L2-3.7.5 requires the addition of multifactor authentication for remote maintenance sessions.
Example
As a system administrator you are responsible for implementing a remote network access capability for users who work offsite. In order to provide session confidentiality, you decide to implement a VPN mechanism and select a product that has completed FIPS 140 validation [a,b].
Potential Considerations
Are cryptographic mechanisms used for remote access sessions (e.g., Transport Layer Security (TLS) and Internet Protocol Security (IPSec) using FIPS-validated encryption algorithms) defined and implemented [a,b]? Note that simply using an approved algorithm is not sufficient – the module (software and/or hardware) used to implement the algorithm must be separately validated under FIPS 140.
Copyright
Copyright 2020, 2021 Carnegie Mellon University and The Johns Hopkins University Applied Physics Laboratory LLC.
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This material is based upon work funded and supported by the Department of Defense under Contract No. FA8702-15-D-0002 with Carnegie Mellon University for the operation of the Software Engineering Institute, a federally funded research and development center, and under Contract No. HQ0034-13-D-0003 and Contract No. N00024-13-D-6400 with the Johns Hopkins University Applied Physics Laboratory LLC, a University Affiliated Research Center.
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