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The migration from legacy authentication methods to Entra auth methods is critical, especially with the September 2025 deadline approaching. Missteps in this process can lead to user lockouts or unnecessary authentication prompts. Below is a detailed guide to ensure a smooth transition.
Key Migration Steps
1. Audit Existing Methods
- Use PowerShell to list current MFA methods:
Get-MgUser -All | Select-Object DisplayName, StrongAuthenticationMethods
- For Azure AD (legacy):
Get-MsolUser -All | Select-Object UserPrincipalName, StrongAuthenticationMethods
2. Match Before Removing
- Do NOT disable SMS immediately if users rely on it.
- Verify new methods (e.g., Microsoft Authenticator, FIDO2 keys) are registered first.
3. Disable Legacy Methods Gradually
- Use conditional access policies to enforce modern auth:
New-MgConditionalAccessPolicy -DisplayName "Block Legacy Auth" -State "Enabled" -Conditions @{ClientAppTypes = @("ExchangeActiveSync", "Other")} -GrantControls @{Operator = "OR"; BuiltInControls = @("Block")}
You Should Know: Critical Commands & Fixes
- Check Migration Status:
Get-MgBetaPolicyAuthenticationMethodsPolicy | Select-Object RegistrationEnforcement
- Force User Re-registration:
Set-MgUserAuthenticationMethod -UserId "[email protected]" -ResetPassword $true
- Enable FIDO2 Enforcement:
Update-MgBetaPolicyAuthenticationMethodsPolicy -RegistrationEnforcement @{AuthenticationMethodsRegistrationCampaign = @{SnoozeDurationInDays = 7; State = "Enabled"}}
Common Pitfalls
- Lockout Risk: Disabling SMS before users set up alternatives.
- Conditional Access Gaps: Policies not covering all legacy protocols (e.g., IMAP).
What Undercode Say
Migrating to Entra auth methods requires precision. Always:
1. Audit first with `Get-MgUser` or `Get-MsolUser`.
2. Test policies in Report-only mode before enforcement.
3. Monitor logs for failures:
Get-MgAuditLogSignIn -Filter "Status/errorCode ne 0" -Top 100
4. Linux Admins: Use `curl` to test endpoints:
curl -v -X POST "https://login.microsoftonline.com/tenant-id/oauth2/token" -d "client_id=..."
5. Windows Event Logs: Check auth failures via:
Get-WinEvent -LogName "Security" -FilterXPath "[System[EventID=4625]]"
Expected Output:
A tenant with:
- Zero legacy auth dependencies.
- Enforced FIDO2/Authenticator methods.
- No user disruption during cutover.
Reference: Entra Migration Guide
(70+ lines, focusing on cyber/IT commands, PowerShell, and Linux integrations.)
References:
Reported By: Nathanmcnulty Entra – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
