Top 7 Microsoft 365 Security Settings Every Small Business Should Turn On Today
- Hanna Korotka
- 2 hours ago
- 2 min read
Many small businesses assume Microsoft 365 is secure by default. While it includes strong protections, many critical security features must be enabled or configured to protect against common threats like phishing, credential theft, and data leaks.
This guide covers 7 essential Microsoft 365 security settings that provide immediate protection with minimal complexity—based on Microsoft recommendations and built-in tools.
1. Enable Multi-Factor Authentication (MFA) for All Users
Why it matters: Passwords alone are not enough. MFA adds a second verification step and significantly reduces the risk of account compromise.
What to do
Ensure MFA is enabled for all users and admins
Prefer Microsoft Authenticator or passkeys where possible
Avoid relying only on passwords
2. Turn On Security Defaults (Quick Baseline Protection)
Why it matters: Security Defaults provide a quick way to apply baseline protections across your organization without complex setup.
What to do
Enable Security Defaults if you are not using Conditional Access
This automatically enforces MFA, blocks legacy authentication, and protects privileged accounts
3. Block Legacy Authentication
Why it matters: Legacy authentication protocols do not support modern security controls like MFA and are commonly used in attacks.
What to do
Disable legacy authentication
Ensure all apps and devices use modern authentication
This removes one of the most common entry points for attackers.
4. Require Secure Sign-Ins with Conditional Access
Why it matters: Not every sign-in should be treated equally. Conditional Access allows you to control access based on risk, device, and location.
What to do
Require MFA for all users
Apply stricter policies for administrators
Use risk-based policies if available
Conditional Access is a key component of a secure identity strategy and helps prevent unauthorized access.
5. Enable Anti-Phishing Protection
Why it matters: Email-based attacks remain the most common threat to small businesses.
What to do
Enable anti-phishing policies in Microsoft Defender
Turn on impersonation protection for key users (executives, finance, HR)
Use preset security policies for quick deployment
Anti-phishing capabilities help detect spoofing, impersonation, and fraudulent messages.
6. Require Compliant Devices for Access
Why it matters: Even if accounts are secure, devices can still create risk if they are not properly configured.
What to do
Define device compliance rules (encryption, OS version, password protection)
Mark devices without compliance policies as noncompliant
Block access from devices that do not meet requirements
Device compliance policies ensure that only secure devices can access company data.
7. Review Your Microsoft Secure Score
Why it matters: Most businesses are unaware of their current security gaps.
What to do
Review Microsoft Secure Score regularly
Focus on high-impact recommendations first
Track improvements over time
Secure Score provides a measurable way to improve your overall security posture.
Final Thoughts
These Microsoft 365 security settings provide a strong, practical foundation for protecting your business.
You don’t need complex tools or enterprise-level projects—just enabling the right configurations can significantly reduce risk and prevent common attacks.
If you’re not sure which of these settings are already in place — or want to make sure they’re configured correctly — we can help review your Microsoft 365 environment and identify gaps. We typically assist with implementing baseline security settings, improving protection step by step, and ensuring changes don’t disrupt day‑to‑day work.