Multifactor Authentication
Use multifactor authentication for local and network access to privileged accounts and for network access to non-privileged accounts.
What an assessor scores, the objectives
IA.L2-3.5.3 is met only when every one of these 4 objectives, from NIST SP 800-171A, is satisfied. A single missed objective makes the whole requirement not met.
- a.privileged accounts are identified
- b.multifactor authentication is implemented for local access to privileged accounts
- c.multifactor authentication is implemented for network access to privileged accounts
- d.multifactor authentication is implemented for network access to non-privileged accounts
How a C3PAO checks it
NIST SP 800-171A defines three assessment methods. For IA.L2-3.5.3, an assessor uses these:
Identification and authentication policy; procedu res addressing user identification and authentication; system security plan; system design documentation; system configuration settings and associated documentation; system audit logs and records; list of system accounts; other relevant documents or records
Personnel with authenticator management responsibilities; personnel with information security responsibilities; system or network administrators
Mechanisms supporting or implementing authenticator management capability
What it means, in context
Multifactor authentication requires the use of two or more different factors to authenticate. The factors are defined as something you know (e.g., password, personal identification number [PIN]); somethin g you have (e.g., cryptographic identification device, token); or something you are (e.g., biometric) . Multifactor authentication solutions that feature physical authenticators include hardware authenticators providing time-based or challenge-response authenticators and smart cards . In addition to authenticating users at the system level (i.e., at logon), organizations may also employ authentication mechanisms at the application level, when necessary, to provide increased information security . Access to organizational systems is defined as local access or network access. Local access is any access to organizational systems by users (or processes acting on behalf of users) where such access is obtained by direct connections without the use of networks . Network access is access to systems by users (or processes acting on behalf of users) where such access is obtained through network connections (i.e., nonlocal accesses) . Remote access is a type of network access that involves communication through external networks. The use of encrypted virtual private networks for connections between organization-controlled and non-organization controlled endpoints may be treated as internal networks with regard to protecting the confidentiality of information. NIST SP 800-63-3 provides guidance on digital identities.
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 ac cess 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].
What passing evidence looks like
The named list of your privileged accounts, then MFA enforced on local and network access for those accounts and on network access for everyone else. The Conditional Access policy or 2SV enforcement screenshot, the privileged account list, and a per user MFA status export.
Common ways contractors fail IA.L2-3.5.3
- !Scoring is special here: MFA for remote and privileged only is a 3 point deduction instead of 5 when the rest is missing, and that partial credit question is asked on your score, inside step 5, Self assessment. Aim for everyone, everywhere anyway.
- !SMS is weak but compliant; authenticator app or keys read better in assessment. What fails is any exempted account quietly excluded from the policy, check exclusions.
The step by step walkthrough for Microsoft 365 GCC High, Google Workspace, and on premises setups, plus the exact evidence to capture, lives inside the Level 2 Accelerator.
Prove IA.L2-3.5.3, and the other 109
The Level 2 workspace walks all 110 requirements with you at the objective level, generates your SSP, POA&M, and Audit Room from real evidence, gives your assessor a read only seat, and puts a Registered Practitioner alongside you year round.
No credit card, and Level 1 and Level 2 are both open, so sign up for the level your contracts call for. Self assessment and self attestation are law today, DFARS 252.204-7012 is unaffected, and the NIST SP 800-171 Rev 2 baseline is unchanged, so the Level 2 work counts either way.
IA.L2-3.5.3 questions, answered
How many points is CMMC requirement IA.L2-3.5.3 worth?+
IA.L2-3.5.3 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 IA.L2-3.5.3 be placed on a POA&M?+
No. IA.L2-3.5.3 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 IA.L2-3.5.3 belong to?+
IA.L2-3.5.3 is in the Identification & Authentication (IA) family, one of the 14 families of NIST SP 800-171 that make up CMMC Level 2.
- NIST SP 800-171 Rev. 2 3.5.3