NIST authenticator assurance level 1 with Microsoft Entra ID

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10/23/2023

The National Institute of Standards and Technology (NIST) develops technical requirements for US federal agencies implementing identity solutions. Organizations must meet these requirements when working with federal agencies.

Before you begin authenticator assurance level 1 (AAL1), you can review the following resources:

NIST overview: Understand AAL levels
Authentication basics: Terminology and authentication types
NIST authenticator types: Authenticator types
NIST AALs: AAL components, Microsoft Entra authentication methods, and Trusted Platform Modules (TPMs).

Permitted authenticator types

To achieve AAL1, you can use any NIST single-factor or multifactor permitted authenticator.

Microsoft Entra authentication method	NIST authenticator type
Password	Memorized Secret
Phone (SMS): Not recommended	Single-factor out-of-band
Microsoft Authenticator App (Passwordless)	Multi-factor out-of-band
Single-factor software certificate	Single-factor crypto software
Multi-factor Software Certificate (PIN Protected) Windows Hello for Business with software TPM	Multi-factor crypto software
Hardware protected certificate (smartcard/security key/TPM) FIDO 2 security key Windows Hello for Business with hardware TPM	Multi-factor crypto hardware

Tip

We recommend you select at a minimum phishing resistant AAL2 authenticators. Select AAL3 authenticators as necessary for business reasons, industry standards, or compliance requirements.

FIPS 140 validation

Verifier requirements

Microsoft Entra ID uses the Windows FIPS 140 Level 1 cryptographic module for its authentication cryptographic operations. It's therefore a FIPS 140-compliant verifier required by government agencies.

Man-in-the-middle resistance

Communications between the claimant and Microsoft Entra ID are over an authenticated, protected channel, to resist man-in-the-middle (MitM) attacks. This configuration satisfies the MitM-resistance requirements for AAL1, AAL2, and AAL3.