Microsoft 365 External Sharing: Maintaining Information Security

Before external users can access your data, you need to have policies to guide your Microsoft 365 external sharing policies, including access limits and safeguards to minimize information security risks.

In today’s interconnected business world, collaboration extends far beyond the walls of your organization. Microsoft 365 recognizes this reality and offers tools for sharing and collaborating with external partners, clients, and vendors as well as within different groups within your company. As we dive into the world of Microsoft 365 external sharing, we’ll also explore how to harness its full potential while safeguarding your organization’s sensitive information.

We’ll cover security best practices, explore the various sharing options available, and highlight the importance of proactive planning in your Microsoft 365 strategy.

Internal and External Microsoft Collaboration Tools

Microsoft 365 offers versatile file and content-sharing capabilities through SharePoint, OneDrive, and Microsoft Teams. These features let you share content with external partners, vendors, customers, and clients, and among licensed users in your organization across multiple Microsoft 365 subscriptions.

The sharing options are highly flexible, ranging from individual files to entire teams, channels, libraries, or sites. It’s important to note that an external user, or outside party, is defined as someone who does not have an account registered or licensed in your specific Microsoft 365 tenant. This comprehensive sharing functionality enhances collaboration both internally and externally, making Microsoft 365 a powerful tool for organizations of all sizes.

While sharing within your organization is fairly simple, sharing with external users requires preparation, so it should be part of the overall permissions planning for SharePoint, OneDrive, and Teams.

In Microsoft 365, there are two main types of external users:

• Guest users: These are users invited to collaborate with your organization. They can access resources like Microsoft Teams, SharePoint, and OneDrive. Guest users can have almost the same capabilities as internal users, depending on the permissions granted to them.
• External users: These users can interact with your organization through external access. This allows them to find, call, and chat with people in your organization using their own Microsoft identities. External users are typically from other organizations that also use Microsoft 365.

The first step is knowing what you can share with people outside the organization and how to categorize it. What comes next is a governance structure for the sharing that you do and don’t want to do.

Establishing Formats and Controls for Microsoft 365 External Sharing

An organization should start by defining clear policies that align with its security and compliance requirements. This involves configuring sharing settings across Microsoft Entra ID, SharePoint, OneDrive, and Teams to ensure that external collaboration is both secure and efficient.

Here are some key sharing scenarios for Microsoft 365 external sharing that organizations can establish:

Collaborate on Documents

Organizations can enable external sharing to allow collaboration on documents with people outside the organization. This scenario is ideal for sharing files and folders with partners, vendors, or clients who need to review or edit documents. By configuring sharing settings in OneDrive and SharePoint, users can share documents with external users either by sending a link or inviting them as guests.

This approach ensures that external collaborators can access the necessary documents while maintaining control over who can view or edit the content. Additionally, organizations can set expiration dates for shared links and require external users to authenticate before accessing the documents.

Collaborate in a Site

For more extensive collaboration needs, organizations can share entire SharePoint sites with external users. This scenario is useful for projects that require ongoing collaboration with external partners or clients. By sharing a site, external users can access all the resources within that site, including documents, lists, and libraries. Organizations can manage permissions at the site level to ensure that external users have the appropriate access rights.

This setup allows for a more integrated and seamless collaboration experience, as external users can navigate and contribute to the site just like internal users.

Collaborate as a Team

Microsoft Teams provides robust capabilities for external collaboration by allowing organizations to add external users as guests to teams. This scenario is particularly beneficial for cross-functional projects that involve both internal and external stakeholders.

By adding external users to a team, organizations can facilitate real-time communication and collaboration through chat, meetings, and file sharing. Teams also offer shared channels, which enable collaboration with external users without adding them to the entire team. This flexibility helps organizations maintain security and control while enabling effective collaboration.

Collaborate with External Participants in a Channel

Shared channels in Microsoft Teams allow organizations to collaborate with external participants within specific channels. This scenario is ideal for focused collaboration on specific topics or projects without granting access to the entire team.

Shared channels enable external users to participate in conversations, share files, and join meetings within the channel. This targeted approach helps organizations manage external collaboration more effectively by limiting access to only the relevant information and resources.

Collaborate with Guests from Other Microsoft 365 Cloud Environments

Organizations that need to collaborate with users from other Microsoft 365 cloud environments, such as commercial or government environments, can configure cross-tenant access settings. This scenario allows for seamless collaboration across different Microsoft 365 tenants, enabling users to share resources and participate in meetings and chats. By setting up organizational relationships and configuring cross-tenant access, organizations can ensure secure and compliant collaboration with external users from different cloud environments.

By understanding and implementing these sharing scenarios, organizations can establish effective formats and controls for external sharing in Microsoft 365, ensuring secure and productive collaboration with external partners, vendors, and clients.

Governance and security go hand in hand, both necessitating a structured approach.

Mitigating Information Security Risks

Once you determine how you want to share content with external users – but before you begin sharing – you must guard against exposing that content to accidental or intentional sharing. This includes protecting against sharing with unintended users by external users who have full control, as well as changes made by anonymous users, which you cannot track.

Microsoft 365 offers processes, settings, and tools that can mitigate these risks, including best practices for sharing with unauthenticated users. Thus, Microsoft 365 can help you create a secure guest-sharing environment that meets your governance obligations.

When sharing corporate assets and intellectual property with external users, it’s crucial to implement robust security measures to protect your data. Some best practices to consider include:

• Enable Multifactor Authentication (MFA): Multifactor authentication adds an extra layer of security by requiring users to verify their identity through multiple methods before accessing Microsoft 365 services. This significantly reduces the risk of unauthorized access.
• Use Sensitivity Labels: Sensitivity labels help classify and protect your data based on its sensitivity. By applying these labels, you can control access, enforce encryption, and ensure that sensitive information is handled appropriately, even when shared externally.
• Implement Data Loss Prevention (DLP) Policies: DLP policies help prevent the accidental sharing of sensitive information. By configuring DLP policies, you can monitor and control the flow of data, ensuring that sensitive information is not shared with unauthorized users.
• Configure Conditional Access Policies: Conditional Access policies allow you to control access to your Microsoft 365 environment based on specific conditions, such as user location, device compliance, and risk level. This ensures that only trusted users and devices can access your corporate data.
• Use Secure Sharing Options: When sharing files and documents externally, use secure sharing options such as OneDrive and SharePoint. These platforms offer granular sharing controls, allowing you to specify who can view or edit the content and set expiration dates for access.
• Enable Safe Links and Safe Attachments: Safe links and safe attachments in Microsoft Defender for Office 365 help protect against malicious links and attachments in emails and documents. These features scan content in real-time and block access to harmful content, providing an additional layer of security.
• Apply Zero-Trust Principles: Adopt a zero-trust security model, which assumes that threats could be both external and internal. This approach involves verifying every access request, enforcing least privilege access, and continuously monitoring for suspicious activities.
• Regularly Review and Update Security Policies: Security threats are constantly evolving, so it’s essential to regularly review and update your security policies. Stay informed about the latest security trends and ensure that your Microsoft 365 environment is configured to address new threats.

Upfront Planning Is Key

When it comes to sharing or collaborating with partners and customers, it is critical to include Microsoft 365 external sharing as part of your governance and security planning – and to ensure users and administrators observe and follow good practices and policies in both areas.

Because many aspects of external sharing are unique to every organization, your organization should make decisions on external sharing policies during the configuration planning phase for any Microsoft 365 implementation project. That way, you can realize the value of Microsoft 365 without compromising your intellectual property, corporate assets, or legal compliance.

Do you want to fully tap into all Microsoft 365 has to offer? Our Modern Workplace experts can guide you through best practices to make your collaboration efforts seamless. Talk to an expert