IA.L2-3.5.3  

Reference: CMMC v2.13

Family: IA

Level Introduced: 2

Title: Multifactor Authentication

Practice:
Use multifactor authentication for local and network access to privileged accounts and for network access to non-privileged accounts.

Further Discussion:
Implement a combination of two or more factors of authentication to verify privileged account holders’ identity regardless of how the user is accessing the account. Implement a combination of two or more factors for non-privileged users accessing the system over a network.

The implementation of multi-factor authentication will depend on the environment and business needs. Although two-factor authentication directly on the computer is most common, there are situations (e.g., multi-factor identification for a mission system that cannot be altered) where additional technical or physical solutions can provide security. If a mobile device is used to access a system or application containing CUI, multi-factor authentication is required.

This requirement, IA.L2-3.5.3, requires multifactor authentication for network access to non-privileged accounts and complements five other requirements dealing with remote access (AC.L2-3.1.12, AC.L2-3.1.14, AC.L2-3.1.13, AC.L2-3.1.15, 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.L2-3.1.13 requires the use of cryptographic mechanisms when enabling remote sessions.
• AC.L2-3.1.15 requires authorization for privileged commands executed during a remote.
• Finally, MA.L2-3.7.5 requires the addition of multifactor authentication for remote maintenance sessions.

This requirement, IA.L2-3.5.3, also enhances IA.L2-3.5.2, which is a requirement for a less rigorous form of user authentication.

Example
You decide to implement multifactor authentication (MFA) to improve security of your network. Your first step is enabling MFA on VPN access to your internal network [c,d]. When users initiate remote access, they will be prompted for the additional authentication factor. Because you also use a cloud-based email solution, you require MFA for access to that resource as well [c,d]. Finally, you enable MFA for both local and network logins for the system administrator accounts used to patch and manage servers [a,b,c].

Potential Assessment Considerations
• Does the system uniquely identify and authenticate users, including privileged accounts [b,c,d]?

Source: CMMC v2.13