Microsoft 365 security
Microsoft 365 security for businesses
Microsoft 365 should be secured correctly from the beginning: MFA, admin permissions, data sharing, mailboxes, devices, user groups and offboarding workflow. IT Systems reviews configuration to reduce the risk of account takeover, spoofed email, data exposure or incorrect sharing permissions.
Reduce account risk
MFA and sign-in
Enable multi-factor authentication, control admin accounts and reduce account takeover risk.
Email and domain
Review SPF, DKIM, DMARC, spoofing protection and basic email policies.
Data and devices
Control OneDrive/SharePoint sharing, access rights and user devices.
Microsoft 365 security checklist
Admin accounts
Separate admin accounts, enable MFA and avoid using admin accounts for daily tasks.
Users
MFA, passwords, permission groups and account lockout process when employees leave.
Email security
SPF/DKIM/DMARC, phishing warnings, aliases/groups and abnormal forwarding rules.
SharePoint/OneDrive
Control external sharing, folder permissions and sensitive data.
Related services
Review Microsoft 365 pricing, Microsoft 365 deployment, Copilot readiness and Microsoft 365 for business before upgrading security policies.
Practical case
Practical case: when a business suspects an email password leak, changing the password alone is not enough. IT Systems checks MFA, sign-in sessions, forwarding rules, connected devices, mailbox permissions and domain policies to prevent continued account abuse.
Microsoft 365 security checklist table
| Area | Best fit | Deployment note |
|---|---|---|
| MFA and admin | Every business using Microsoft 365 email. | Enable MFA, separate admin accounts and check sign-in sessions. |
| Email domain | Businesses sending email with their own domain. | Review SPF/DKIM/DMARC and abnormal rules. |
| Internal data | Businesses using SharePoint/OneDrive or sensitive data. | Control external sharing and folder permissions. |
Need a Microsoft 365 security review?
FAQ: Microsoft 365 security should start with MFA and admin accounts; email should have SPF, DKIM and DMARC; OneDrive/SharePoint need external sharing control; Business Premium is suitable when stronger security and device management are required.