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
Explore the specialist controls: MFA for Microsoft 365, Conditional Access, Microsoft Intune and Defender for Endpoint. Review Microsoft 365 pricing before selecting licenses.
Illustrative scenario
A common scenario when an email password leak is suspected: changing the password alone is not enough. Review MFA methods, active sign-in sessions, forwarding rules, connected applications and devices, mailbox permissions, administrator accounts and domain policies; then revoke sessions, remediate abnormal settings and retain review evidence.
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?
Send us your current tenant, licensing, user and administrator count, managed devices, MFA configuration, email domain and SharePoint or OneDrive scope. IT Systems will assess the current state, classify risks and propose a controlled pilot. Conditional Access, Intune, Defender and other advanced controls require eligible licensing.