Expert Answer

What is Security Defaults in Microsoft 365?

Quick Answer

Security Defaults is a free security baseline that enables MFA for all users, blocks legacy authentication, and requires MFA for admin roles. It is recommended for organizations without Conditional Access licenses but provides less flexibility.

Detailed Explanation

Security Defaults is Microsoft's free, pre-configured set of identity security settings designed to protect organizations from the most common attacks.

What Security Defaults enables: 1. MFA registration required for all users within 14 days 2. MFA enforcement for admins immediately 3. MFA challenge for all users when needed (risk-based) 4. Legacy authentication blocked (IMAP, POP3, etc.) 5. Protection of privileged actions (require MFA)

  • *Who should use Security Defaults:
  • Organizations without Entra ID P1/P2 licenses
  • Small businesses without security staff
  • Organizations just starting their security journey
  • Testing/development tenants
  • *Who should NOT use Security Defaults:
  • Organizations using Conditional Access (mutually exclusive)
  • Organizations needing custom MFA requirements
  • Organizations with legacy apps that need temporary exceptions
  • Organizations requiring granular location-based policies
**Limitations vs Conditional Access:**
| Feature | Security Defaults | Conditional Access |
|---------|------------------|-------------------|
| Cost | Free | Requires P1/P2 |
| Customization | None | Full control |
| Exceptions | None possible | Granular exclusions |
| Legacy auth | Complete block | Selective block |
| Named locations | Not available | Available |
| Device compliance | Not available | Available |

Important: You cannot enable both Security Defaults and Conditional Access policies. Choose one approach.

TrueConfig recommends Conditional Access for production tenants needing flexibility.

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