Best Practices for Microsoft Teams Guest Access

In the last few years, Microsoft Teams has emerged as an incredibly powerful tool for teamwork. It enables organizations and teams to move beyond many limitations of virtual communication and collaboration. Microsoft Teams makes it easier than ever to collaborate with the right people – whether they are inside or outside your organization.

For most organizations, collaboration with external members is vital for smooth operations. Microsoft Teams delivers seamless and intuitive experiences to strengthen external collaboration. Leveraging Microsoft Teams’ guest access experience, people within your organization can effortlessly interact and engage with partners, vendors, customers, and others who don’t have an account in your directory.

What is External Access in Teams?

External access enables employees within your organization to find, call, chat and set up meetings with people in other organizations using Teams. It facilitates seamless collaboration and communication between users from two different organizations. External access can be leveraged when:

• You have users in different domains who need to collaborate.
• You want users in your organization to use Teams to contact people in specific businesses outside of your organization.
• You want anyone else in the world who uses Teams to be able to find and contact you, using your email address.

What is Guest Access in Teams?

Guest access, a part of the external access experience, lets users collaborate with people outside your organization by granting them access to teams and channels. Guest users can participate in chats and channel conversations, create channels, make calls, set up meetings, and access shared files. This feature should be leveraged only when you want users from outside of your organization to inherit most of the privileges of a native team member, except access to OneDrive for Business and Calendar. Some situations that may require guest access levels include the following:

• Your existing team could use advice or assistance from a former co-worker or business partner, who used to be the authority on the subject. However, providing the usual access levels to a former employee is not the best way to do this. It’s probably safer to provide guest access that limits the former co-worker to documents and communications that pertain to their expertise.
• You have an external contractor or consultant who helps on specific areas of a project. In such scenarios, it makes sense to grant access to the relevant areas only, and not the entire project.
• You have a vendor or supplier who needs access to specific internal resources and collaboration with an internal person in charge to integrate their provided solution.

How to create a safe Guest Access environment?

When used correctly, guest access can be just as easy as collaborating internally. When used incorrectly, however, it can cause a nightmare of sensitive data leakage and loss. To avoid this scenario, it is vital to implement precautionary measures when sharing files externally or having guests around. This way, you don’t inadvertently provide guest permissions to areas that should have stayed private. Managing guest access security also ensures that external collaboration doesn’t have to come at the cost of Teams security. Some of the security measures you may implement include:

• Implement multi-factor authentication: Multi-factor authentication significantly reduces the chances of an account being compromised. Since guests may be using personal email accounts that don’t adhere to your organization’s governance policies or best practices, it is especially important to require multi-factor authentication for guests.
• Create detailed terms of use: In some situations, guests may not have signed non-disclosure agreements or other legal agreements with your organization. You can require guests to agree to terms of use before accessing files that are shared with them. The terms of use can be displayed the first time they attempt to access a shared file or site.
• Set up quarterly guest access audits to remove dormant or dead accounts and review access permissions for existing guests: Utilize access reviews in Azure AD to automate a periodic review of guest user access to various teams and groups. By requiring an access review for guests specifically, you can help ensure guests do not retain access to your organization’s sensitive information for longer than what is necessary.
• Restrict gests to web-only access when using an unregistered device: Organizations can narrow down risk surface and ease administration by requiring guests to access your teams, sites, and files by using a web browser only. For Teams, this can be done with an Azure AD conditional access policy.
• Configure a session timeout policy to ensure frequent guest authentications: Implementing a session timeout policy, encourages the guest user to authenticate regularly. It can significantly reduce the chances of unknown users accessing your organization’s content if the guest user’s device isn’t kept secure. This policy can be configured for guests in Azure AD.
• Identify and label sensitive files and documents: Sensitive information types are predefined strings that can be used in policy workflows to enforce compliance requirements. The Microsoft 365 Compliance Center comes with over one hundred sensitive information types. If you are using sensitivity labels in your organization, you can automatically apply a label to files that contain sensitive information.

Grant Inclusive or Restrictive Microsoft Azure Permission Levels

For additional guest access security, you can assign permission levels to your guests using the guest user restrictions policy controls in Azure Active Directory. These controls let you assign different policy options to each guest, ranging from most inclusive to the most restrictive.

• You can assign the same access levels as members, allowing the guests access to directory data as any regular Teams members.
• You may limit the access of guest users from performing certain directory tasks, including using Microsoft Graph for enumerating users, groups, or other directory resources.
• You can restrict guest access to properties and memberships of their own directory objects, wherein the guests can only access their own directory objects.

Guest access has emerged as a strong Microsoft Teams capability, especially in the ongoing hybrid working scenario. With its flexible permission policies and a wide range of configuration options, Teams enables your organization’s users to communicate and collaborate with external users in secure ways. However, securing and managing guest access in Teams can be a tedious process.

Unleash the Complete Potential of Microsoft Teams with Nippon Data

As a Microsoft Gold Partner and Cloud Solutions Provider, Nippon Data has been enabling organizations to unlock more ways to work together. Our Microsoft Teams Security & Governance services allow organizations to overcome the loopholes in external access management and experience the next-level collaboration in Microsoft Teams. Want to learn more? Contact us now.