Auth0 Mfa

Auth0 MFA Guide

Add Multi-Factor Authentication to protect user accounts and require additional verification for sensitive operations.

Overview

What is MFA?

Multi-Factor Authentication (MFA) requires users to provide two or more verification factors to access their accounts. Auth0 supports multiple MFA factors and enables step-up authentication for sensitive operations.

When to Use This Skill

• Adding MFA to protect user accounts
• Requiring additional verification for sensitive actions (payments, settings changes)
• Implementing adaptive/risk-based authentication
• Meeting compliance requirements (PCI-DSS, SOC2, HIPAA)

MFA Factors Supported

| Factor | Type | Description |

|--------|------|-------------|

| TOTP | Something you have | Time-based one-time passwords (Google Authenticator, Authy) |

| SMS | Something you have | One-time codes via text message |

| Email | Something you have | One-time codes via email |

| Push | Something you have | Push notifications via Auth0 Guardian app |

| WebAuthn | Something you have/are | Security keys, biometrics, passkeys |

| Voice | Something you have | One-time codes via phone call |

| Recovery Code | Backup | One-time use recovery codes |

Key Concepts

| Concept | Description |

|---------|-------------|

| acr_values | Request MFA during authentication |

| amr claim | Authentication Methods Reference - indicates how user authenticated |

| Step-up auth | Require MFA for specific actions after initial login |

| Adaptive MFA | Conditionally require MFA based on risk signals |

Step 1: Enable MFA in Tenant

Via Auth0 Dashboard

• Go to Security → Multi-factor Auth
• Enable desired factors (TOTP, SMS, etc.)
• Configure Policies:
• Always - Require MFA for all logins
• Adaptive - Risk-based MFA
• Never - Disable MFA (use step-up instead)

Via Auth0 CLI

# View current MFA configuration
auth0 api get "guardian/factors"

# Enable TOTP (One-time Password)
auth0 api put "guardian/factors/otp" --data '{"enabled": true}'

# Enable SMS
auth0 api put "guardian/factors/sms" --data '{"enabled": true}'

# Enable Push notifications
auth0 api put "guardian/factors/push-notification" --data '{"enabled": true}'

# Enable WebAuthn (Roaming - Security Keys)
auth0 api put "guardian/factors/webauthn-roaming" --data '{"enabled": true}'

# Enable WebAuthn (Platform - Biometrics)
auth0 api put "guardian/factors/webauthn-platform" --data '{"enabled": true}'

# Enable Email
auth0 api put "guardian/factors/email" --data '{"enabled": true}'

Configure MFA Policy

# Set MFA policy: "all-applications" or "confidence-score"
auth0 api patch "guardian/policies" --data '["all-applications"]'

Step 2: Implement Step-Up Authentication

Step-up auth requires MFA for sensitive operations without requiring it for every login.

The acr_values Parameter

Request MFA by including acr_values in your authorization request:

acr_values=http://schemas.openid.net/pape/policies/2007/06/multi-factor

Implementation Pattern

The general pattern for all frameworks:

• Check if user has already completed MFA (inspect amr claim)
• If not, request MFA via acr_values parameter
• Proceed with sensitive action once MFA is verified

For complete framework-specific examples, see Examples Guide:

• React (basic and custom hook)
• Next.js (App Router)
• Vue.js
• Angular

Additional Resources

This skill is split into multiple files for better organization:

Step-Up Examples

Complete code examples for all frameworks:

• React (basic and custom hook patterns)
• Next.js (App Router with API routes)
• Vue.js (composition API)
• Angular (services and components)

Backend Validation

Learn how to validate MFA status on your backend:

• Node.js / Express JWT validation
• Python / Flask validation
• Middleware examples

Advanced Topics

Advanced MFA implementation patterns:

• Adaptive MFA with Auth0 Actions
• Conditional MFA based on risk signals
• MFA Enrollment API

Reference Guide

Common patterns and troubleshooting:

• Remember MFA for 30 days
• MFA for high-value transactions
• MFA status display
• Error handling
• AMR claim values
• Testing strategies
• Security considerations

Related Skills

• auth0-quickstart - Basic Auth0 setup
• auth0-passkeys - WebAuthn/passkey implementation
• auth0-actions - Custom authentication logic

References

• Auth0 MFA Documentation
• Step-Up Authentication
• MFA API
• acr_values Parameter