Remote Access Confidentiality
Employ cryptographic mechanisms to protect the confidentiality of remote access sessions.
What an assessor scores, the objectives
AC.L2-3.1.13 is met only when every one of these 2 objectives, from NIST SP 800-171A, is satisfied. A single missed objective makes the whole requirement not met.
- a.cryptographic mechanisms to protect the confidentiality of remote access sessions are identified
- b.cryptographic mechanisms to protect the confidentiality of remote access sessions are implemented
How a C3PAO checks it
NIST SP 800-171A defines three assessment methods. For AC.L2-3.1.13, an assessor uses these:
Access control policy; procedures addressing remote access to the system; system security plan; system design documentation; system configuration settings and associated documentation; cryptographic mechanisms and associated configuration documentation; system audit logs and records; other relevant documents or records
System or network administrators; personnel with information security responsibilities; system developers
Cryptographic mechanisms protecting remote access sessions
What it means, in context
Cryptographic standards include FIPS -validated cryptography and NSA- approved cryptography.
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 . 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. Although not explicitly required to meet AC.L2 -3.1.13 requirements, this remote access session must be secured using FIPS -validated cryptography to provide confidentiality and prevent anyone from deciphering session information exchanges. This requirement, AC.L2-3.1.13, requires the use of cryptographic mechanisms when enabling remote sessions and complements five other requirements 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 You are responsible for implementing a remote network access capability for users who access CUI remotely. 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 Assessment Considerations • Are cryptographic mechanisms used for remote access sessions (e.g., Transport L ayer 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.
What passing evidence looks like
A note naming the cryptography protecting each remote path (TLS 1.2+ for cloud, the VPN cipher suite) and a configuration screenshot for each.
Common ways contractors fail AC.L2-3.1.13
- !For the confidentiality of the session this requirement wants cryptographic mechanisms IDENTIFIED and IMPLEMENTED. FIPS validation specifically matters at SC.L2-3.13.11; here, name the mechanism and show it is on.
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Prove AC.L2-3.1.13, and the other 109
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AC.L2-3.1.13 questions, answered
How many points is CMMC requirement AC.L2-3.1.13 worth?+
AC.L2-3.1.13 is worth 5 points in the CMMC Level 2 score under 32 CFR 170.24. If it is not met, you lose 5 from your total of 110.
Can AC.L2-3.1.13 be placed on a POA&M?+
No. AC.L2-3.1.13 must be fully met before you can file. It cannot be deferred to a POA&M, so it is a gate on your assessment.
What family does AC.L2-3.1.13 belong to?+
AC.L2-3.1.13 is in the Access Control (AC) family, one of the 14 families of NIST SP 800-171 that make up CMMC Level 2.
- NIST SP 800-171 Rev. 2 3.1.13