Security is a top priority for organizations using SharePoint Online, as it stores sensitive business data, documents, and collaboration assets. Microsoft provides advanced security features to protect against unauthorized access, data breaches, cyber threats, and insider risks.
This guide explores the key security features, best practices, and advanced protection mechanisms available in SharePoint Online to ensure a secure and compliant environment.
1. Identity and Access Management
1. Multi-Factor Authentication (MFA)
Best for: Preventing unauthorized access by requiring an extra layer of authentication.
How to Enable MFA for SharePoint Online:
- Go to Microsoft Entra ID (formerly Azure AD) → Security → Conditional Access.
- Click New Policy → Choose Users and Groups.
- Select SharePoint Online as the app.
- Under Grant, select Require Multi-Factor Authentication.
- Enable and enforce the policy.
Benefit: Ensures only authorized users can access SharePoint, reducing phishing and credential theft risks.
2. Conditional Access Policies
Best for: Controlling access to SharePoint based on user identity, device, and location.
How to Configure Conditional Access for SharePoint Online:
- Go to Microsoft Entra ID → Security → Conditional Access.
- Click New Policy → Name the policy.
- Under Assignments, select Users or Groups.
- Choose Cloud Apps → Select SharePoint Online.
- Set conditions:
- Allow access only from managed devices.
- Block access from untrusted locations.
- Require MFA for high-risk sign-ins.
- Enable and apply the policy.
Benefit: Prevents unauthorized access from untrusted devices, risky sign-ins, and unknown locations.
2. Data Protection and Governance
3. Data Loss Prevention (DLP) Policies
Best for: Preventing sensitive data from being shared externally.
How to Set Up DLP in SharePoint Online:
- Go to Microsoft Purview Compliance Center → Data Loss Prevention.
- Click Create a Policy → Choose a template (e.g., GDPR, Financial Data, Health Records).
- Select SharePoint and OneDrive as locations.
- Define sensitive data types (e.g., credit card numbers, SSNs).
- Set rules to block sharing or send alerts when sensitive data is detected.
Benefit: Prevents accidental or malicious data leaks and enforces compliance regulations.
4. Sensitivity Labels & Encryption
Best for: Protecting confidential data with encryption and restricted access.
How to Apply Sensitivity Labels in SharePoint:
- Go to Microsoft Purview Compliance Center → Information Protection.
- Click Create Label → Name it (e.g., Confidential, Internal Use, Public).
- Enable encryption and access control settings.
- Apply labels to SharePoint libraries, folders, or files.
Benefit: Ensures sensitive files are encrypted and access-restricted even if downloaded or shared externally.
3. Threat Protection and Risk Management
5. Microsoft Defender for Office 365 (Safe Attachments & Safe Links)
Best for: Protecting SharePoint from malware, ransomware, and phishing attacks.
How Safe Attachments Protects SharePoint:
- Scans all uploaded files in SharePoint for malware and viruses.
- Blocks infected files and prevents users from opening malicious content.
How Safe Links Works in SharePoint:
- Rewrites all URLs in SharePoint documents to scan for phishing sites.
- If a user clicks a malicious link, Microsoft Defender blocks access and alerts admins.
Benefit: Reduces malware infections, phishing attacks, and ransomware risks.
6. Ransomware Protection and File Restore
Best for: Detecting ransomware attacks and restoring files after an attack.
How to Recover from Ransomware in SharePoint:
- Go to the Document Library → Click Settings Gear → Restore this library.
- Select a point-in-time before the ransomware attack.
- Click Restore to revert all changes.
Benefit: Allows quick recovery of files affected by ransomware attacks.
7. Microsoft Defender for Cloud Apps (CASB)
Best for: Detecting insider threats, suspicious activities, and external sharing risks.
How to Enable Defender for Cloud Apps in SharePoint:
- Go to Microsoft Defender for Cloud Apps portal.
- Enable Cloud Discovery to monitor SharePoint Online activities.
- Set alerts for unusual file sharing, mass downloads, and suspicious logins.
- Block risky activities using Conditional Access policies.
Benefit: Helps organizations detect shadow IT risks, insider threats, and data breaches in SharePoint.
4. External Sharing and Guest Access Security
8. External Sharing Controls
Best for: Managing who can access SharePoint files from outside your organization.
How to Restrict External Sharing:
- Go to Microsoft 365 Admin Center → SharePoint Admin Center.
- Click Policies → Sharing.
- Set external sharing levels:
- Only people in your organization (most secure).
- New and existing guests (allows collaboration).
- Anyone with the link (least secure).
- Enable expiration dates for shared links.
Benefit: Prevents data leaks by controlling external file sharing permissions.
9. Expiring Access and Time-Limited Guest Permissions
Best for: Limiting how long guests can access SharePoint content.
How to Enable Expiring Guest Access:
- Go to SharePoint Admin Center → Policies → Sharing.
- Enable Guest access expiration (e.g., 30 days).
- Set up alerts to notify users before access expires.
Benefit: Reduces security risks from inactive or forgotten guest accounts.
5. Compliance and Security Auditing
10. Audit Logs and Insider Risk Detection
Best for: Monitoring user activities, unauthorized access, and suspicious behavior.
How to View SharePoint Online Audit Logs:
- Go to Microsoft Purview Compliance Center → Audit.
- Click Search Audit Log → Select SharePoint and OneDrive.
- Filter logs by file access, permission changes, external sharing, or data deletions.
- Export logs for security audits.
Benefit: Helps identify data breaches, insider threats, and unauthorized access attempts.
6. Best Practices for SharePoint Online Security
✔ Enforce Multi-Factor Authentication (MFA) for all SharePoint users.
✔ Use Conditional Access to block untrusted logins.
✔ Restrict External Sharing to prevent unauthorized access.
✔ Enable Data Loss Prevention (DLP) to protect sensitive files.
✔ Monitor Activity Logs for security threats.
✔ Apply Sensitivity Labels to encrypt confidential data.
✔ Enable Microsoft Defender to scan for malware and phishing threats.