Neither SharePoint Online nor on-premises SharePoint is automatically safer. The key difference is operational responsibility: Microsoft operates the SharePoint Online service and its underlying infrastructure, while the customer still secures identities, permissions, sharing, data governance, and tenant activity. With SharePoint Server, the organization must also operate and harden the farm, servers, databases, and network connections. The right comparison is therefore which risks each deployment leaves your team responsible for—and whether you have the controls and staff to manage them.
How the security responsibilities differ
SharePoint Online is part of Microsoft 365. Microsoft describes service-side safeguards for its cloud service, while customers configure how people and applications access their tenant and how its data is shared and governed. SharePoint Server is deployed in an organization’s own environment; its team is responsible for the farm and its supporting infrastructure as well as access controls.
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Microsoft’s cloud documentation says, “You control your data.” That is a statement about customer ownership and responsibility, not a claim that every security setting is automatically configured for each organization. Microsoft describes its service controls; those descriptions should not be mistaken for an independent comparative audit.
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1Clear out junk files and repair common Windows errors2Fix the driver behind crashes, sound loss and screen glitches3Repair Windows errors before they cause bigger problems| Security area | SharePoint Online | SharePoint Server, on-premises |
|---|---|---|
| Underlying service and infrastructure | Microsoft operates the service and describes datacenter, network, application, encryption, monitoring, and patching safeguards. Customers configure tenant-level protections and data controls. | The organization operates and hardens the farm, servers, databases, network boundaries, and relevant supporting software. |
| Identity and access | The customer configures identity protections, site and content permissions, and sharing. Microsoft recommends two-factor authentication and device-based conditional access. | The customer configures identity protections and SharePoint permissions, and selects authentication methods supported by the deployed version and design. |
| Network and host exposure | Microsoft manages the cloud service infrastructure; the customer still needs to control tenant access, sharing, apps, and administrative activity. | The customer must review server roles, firewalls, required services, Central Administration access, Web.config, and communication with SQL Server and other systems. |
| Monitoring and recovery | Microsoft describes service monitoring, audit options, and recovery features. The organization must decide what tenant activity to monitor and whether recovery meets its requirements. | The organization is responsible for operating its monitoring and recovery arrangements for the farm and supporting infrastructure. |
This is a responsibility comparison, not a ranking by breach frequency: the cited Microsoft product documentation does not establish that one deployment has fewer incidents than the other.
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Control identity and permissions in either deployment
Separate authentication from authorization
Authentication verifies who a user or application is; authorization determines what that identity may do. A successful sign-in does not establish that access to every site, library, folder, or item is appropriate. SharePoint permissions govern access to these objects, and permission inheritance is a common way to apply access consistently.
Use least privilege and manageable access scopes
Give users and groups only the access they need. Prefer group-based assignments and inherited permissions where they meet the business requirement. SharePoint Server supports permissions at site, list or library, folder, and document or item levels; breaking inheritance creates unique assignments. Many unique assignments can be difficult to track and maintain, and Microsoft’s planning guidance warns that extensive fine-grained permissions can increase administration and slow access.
- Identify who owns each site or content area and who approves access.
- Use groups for roles or teams rather than accumulating individual grants where practical.
- Review unique permissions and remove exceptions that no longer have a business purpose.
- Set a recurring access-review process, especially for sensitive content and external users.
These practices apply to both deployment models. A well-protected sign-in does not correct excessive permissions, and tidy permissions do not protect an account whose credentials have been compromised.
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What to configure in SharePoint Online
Microsoft’s guidance, “How SharePoint and OneDrive safeguard your data in the cloud” (last updated January 13, 2025), describes service safeguards and recommends customer-configurable controls. Exact capabilities and policy options can depend on the Microsoft 365 tenant configuration and licensing.
Protect administrator and user identities
- Enable two-factor authentication for Microsoft 365 identities, starting with Global Administrators and then other administrators and site collection administrators, as Microsoft recommends.
- Use device-based conditional access to limit access from unmanaged devices where the organization’s policy and licensing support it.
- Review who holds administrative roles and remove access that is no longer needed.
Reduce exposure through sharing and sessions
- Set external-sharing controls to match business needs, and review them alongside site and content permissions rather than treating a tenant-wide setting as proof that all files are appropriately restricted.
- Consider session sign-out controls and restrictions on unmanaged-device access for the data and users they are intended to protect.
- Review app access and permissions as well as human users; an approved app can still have more access than its task requires.
Govern and monitor tenant data
- Use data loss prevention (DLP) policies to help prevent accidental exposure where the required capabilities are available and configured.
- Decide which audit events and administrative activities your team needs to review, who will respond to alerts, and how long relevant records must remain available.
- Test recovery procedures against business requirements instead of assuming a service feature alone satisfies them.
Microsoft describes its service-side controls as including encryption in transit and at rest; datacenter, network, and application protections; antimalware scanning on upload; service monitoring and patching; and compliance and audit resources. It also says engineer access is restricted, time-limited, approved, and recorded in audit events. These are Microsoft’s descriptions of its service safeguards, not a guarantee against tenant misconfiguration, unsafe sharing, compromised identities, or poor data governance.
What to harden in SharePoint Server
For an on-premises deployment, customer responsibility extends to the farm and its connections. Microsoft’s “Plan security hardening for SharePoint Server” (last updated January 19, 2023) says hardening depends on server role and does not cover hardening every other software product in the environment. Apply guidance to the actual SharePoint and Windows Server versions and topology rather than treating a generic port list as a universal firewall recipe.
- Farm boundaries: Review firewall placement between farm servers and outside requests, and expose only the connections required by the deployed design.
- Server roles and services: Confirm which roles and service applications are enabled, retain required services, and disable or restrict what the farm does not need.
- Administrative interfaces: Restrict access to Central Administration to appropriate administrators and management paths.
- Configuration files: Apply the relevant hardening guidance to Web.config and protect configuration changes through controlled administration.
- Database and application traffic: Review SQL Server communication ports and application-specific connections against enabled services and external dependencies.
- Environment beyond SharePoint: Include operating systems, databases, network devices, and other software in the security plan; the SharePoint hardening guidance does not secure those products on your behalf.
The exact allowed traffic and network boundaries depend on farm topology, enabled roles, service applications, external connections, and supported product configurations. Validate the design for the specific SharePoint Server and Windows Server versions in use.
Authentication choices and application trust on-premises
SharePoint Server authentication options vary by version and configuration. Microsoft’s “Authentication overview for SharePoint Server” (last updated January 19, 2023) documents Windows, forms-based, SAML, and OpenID Connect (OIDC)-based claims authentication; it identifies OIDC 1.0 support for SharePoint Server Subscription Edition. Confirm applicability for the deployed version rather than assuming every option is available in every farm.
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User sign-in is only one trust boundary. Apps and server-to-server connections have their own authorization and trust requirements. Microsoft’s “Plan for server-to-server authentication in SharePoint Server” (last updated January 19, 2023) explains that server-to-server OAuth trust is distinct from user authentication, requires appropriate trust and permissions, and requires SSL on web applications with incoming or outgoing server-to-server endpoints. Review each integration’s permissions and trust rather than treating it as an ordinary user account.
Recovery claims and what they do—and do not—establish
Microsoft’s cloud safeguards page, last updated January 13, 2025, says metadata backups are retained for 14 days and that metadata can be restored to a point in time within a five-minute window. The same page also describes version history and recycle-bin options. These are dated Microsoft statements about the service; they do not establish identical retention or restoration behavior for every item, tenant, or recovery scenario. Check current service documentation and terms, and map the available options to your organization’s recovery objectives.
For either deployment, define what must be recoverable, the acceptable recovery time and data loss, who can initiate recovery, and how restoration will be tested. In SharePoint Server, include the farm and supporting infrastructure in the recovery plan; cloud service features do not replace a customer’s responsibility to validate its own operational requirements.
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Quick Recap
Practical security review checklist
- Define scope: Record whether the environment is SharePoint Online or SharePoint Server, its product version or edition, tenant configuration, topology, and relevant licensing.
- Map ownership: Assign owners for identity, site permissions, external sharing, app access, monitoring, incident response, and recovery. For SharePoint Server, assign owners for farm, host, database, and network hardening too.
- Check identity and access: Verify administrator protections, authentication choices, group assignments, inherited access, unique permission exceptions, and the access-review process.
- Review exposure paths: In SharePoint Online, assess external sharing, unmanaged-device access, sessions, and application permissions. In SharePoint Server, validate firewall boundaries, required services, Central Administration, Web.config, and farm communications against the actual design.
- Validate monitoring and recovery: Identify the activity your team will monitor, response owners, applicable audit and DLP capabilities, recovery objectives, and evidence that restoration procedures work.
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