Essential Microsoft 365 Security Settings Every Business Needs

Table of Contents

This is non-negotiable. MFA blocks 99.9% of account compromise attacks.

How to Enable: 1. Go to Microsoft 365 Admin Center 2. Navigate to Users > Active Users 3. Select "Multi-factor authentication" 4. Enable for all users, starting with admins

Pro Tip: Use the Microsoft Authenticator app rather than SMS for better security and user experience.

For smaller organizations, Security Defaults provide essential protection with minimal configuration:

Larger organizations should consider Conditional Access policies for more granular control.

Email spoofing is a major attack vector. These three protocols work together to prevent it:

SPF (Sender Policy Framework): Specifies which servers can send email for your domain.

DKIM (DomainKeys Identified Mail): Adds a digital signature to outgoing emails.

DMARC (Domain-based Message Authentication): Tells receiving servers what to do with emails that fail SPF/DKIM.

You can't investigate what you don't log. Unified Audit Logging captures:

To Enable: 1. Go to Microsoft Purview Compliance Portal 2. Navigate to Audit 3. Start recording user and admin activity

Part of Microsoft Defender for Office 365, these features protect against:

Even if you don't have Defender licenses, basic protection is included with Business Premium.

Create alerts for critical events:

Navigate to: Security & Compliance Center > Alerts > Alert policies

OneDrive and SharePoint external sharing is often too permissive by default:

1. Go to SharePoint Admin Center
2. Select Policies > Sharing
3. Restrict to specific domains if possible
4. Require sign-in for external access

Security isn't a one-time setup. Review these monthly:

Proper Microsoft 365 security configuration can feel overwhelming. Our team specializes in helping businesses secure their Microsoft environment. Contact us for a security assessment.