Office 365 Security Best Practices – Keeping Your Work and Documents Safe

For almost a decade, IT professionals have been encouraging companies to move to the cloud. They’ve been pointing out that the cloud proved beneficial for the high availability of companies’ systems and data they hold, as well as overall business continuity in a catastrophic event. And then, in 2020, the COVID-19 pandemic hit companies across the globe.

Those businesses that invested in cloud and collaboration technologies, in general, had a considerable advantage of enabling their employees to work from home during the pandemic. There were many reasons why companies delayed the implementation of cloud technologies, but one of the top concerns was about the security of data in the cloud. In this blog post, we will examine the top Office 365 security best practices and how you can keep your environment secure.

1. Secure Scores

There are two flavors of security reporting the Microsoft 365 platform. One is part of Office 365, and it is called the Secure Score, and the other is part of Azure AD, and it is called the Identity Secure Score. Both tools scan your environment and alert you of tenant configuration improvements you can do to follow the latest security best practices. These tools allow you to learn more about potential threats, how to mitigate them, and which features are there to help you. The tools continuously evolve based on Microsoft research and live system monitoring.

Microsoft secure score

 

2. Audit Logs

Office 365 audit logs help you keep an eye on a continuous stream of events, operations, and user actions in your tenant. I sincerely advise you to enable auditing, as you never know when some critical situation might require it. To ensure you have enabled auditing, navigate to the Audit Log Search.

The audit log provides a comprehensive view of activities in various workloads like Exchange, SharePoint, Microsoft Teams, Groups, Azure AD, and DLP. The built-in search engine helps us find what we are looking for. More advanced users can use the Out-Of-The-Box PowerShell commands to query the log or query data from the APIs directly.

One downside of the built-in approach is that retention of the log is rather short, only 90 days for Office 365 E3 licenses and 365 for E5 (in preview still). One way to extend it would be to use the API and store data in your storage or rely on one of the readily available Office 365 governance tools like SysKit Point.

 

3. Microsoft 365 compliance center

With the Microsoft 365 compliance center, customers can scan their data to verify what kind of data is being hosted within the system. Most often, this will include scanning for personally identifiable documentation across SharePoint, Exchange, and OneDrive workloads but also numerous other scans and compliance scores available as part of the Microsoft Compliance Score.

Welcome to compliance center

4. Multifactor authentication (MFA)

Multifactor authentication requires users to present two or more pieces of evidence (factors) when authenticating. Office 365 has built-in support for MFA, and although it does require a little bit of manual work to enable it for each user, it is a must-have. Users can authenticate via mobile app, text messages, or calls. To further secure the login page, it is strongly recommended companies deploy custom branding for the login page.

Multi factor authentication

 

5. Conditional Access

You can further guard the access to the Office 365 tenant by implementing Azure AD Conditional Access functionality. It allows us to safeguard the tenant based on a myriad of conditions like location, IP address, and application usage. When combined with other AD user properties like department, it is easy to block users from, for example, the Marketing department to connect to Office 365 from a suspicious, non-company location.

 

6. Azure Information Protection

In many Office 365 deployments, the most critical data is often stored in Microsoft Office documents. Azure Information Protection allows us to protect documents from being shared, and , as well as emails to be forwarded. In essence, it encrypts the document, and only authorized, hand-picked personnel can decrypt its contents.

 

7. Cloud App Security

Securing various applications in the cloud presents a new challenge for IT. This is where the Cloud App Security Framework steps in as it helps IT control numerous apps, logs, devices, and more. It helps control shadow IT, protect sensitive information in the cloud, and scan app logs for possible cyber threats and anomalies.

 

8. External Users and Guest

One of the essential capabilities of Office 365 is inviting external users to collaborate with you in SharePoint, OneDrive, and Teams. However, make sure you choose the appropriate sharing policies that would work for your organization. Not all end users are IT savvy enough, so you might want to limit external sharing. The best practice is to allow only people preapproved by IT, called Existing Guests, to participate in the collaboration.

 

9. Sharing Links

On top of external sharing controls, it is crucial to configure the types of sharing links that your users can generate by default. The best practice would be to stick to the option “Specific people (only the people the user specifies).” With this option selected, even if a user forwards a link to someone else in your organization, this user would not be able to open the document.

 

SharePoint Sharing

10. Access Reviews

In our previous blog post, we talked about Office 365 Access Governance where we discussed the Azure AD feature called Access Reviews. By leveraging Access Reviews, Office 365 administrators can streamline user onboarding and offboarding when it comes to managing memberships and access rights. You can also use it for periodical reviews of users with privileged access.

In the cloud, the critical component for the security of business assets is the integrity of your users, especially those who have privileged access to your resources. Multiple accounts and different roles could be considered privileged in complex environments such as Office 365 and Azure. It is of paramount importance to limit their number as soon as possible. Below, I listed a couple of steps that you should do to keep your Office 365 secure!

 

Best Practices Checklist

  • Turn on Azure AD Privileged Identity Management – this allows you to get notifications on each privileged role change.
  • Identify users in the following roles: Global administrator, Privileged role administrator, Exchange Online administrator, and SharePoint Online administrator.
  • Make sure you have at least two emergency users, “break-in” accounts in case of AD sync failure. Consider turning MFA off for these accounts in the event of MFA service failure.
  • Turn on MFA on all other privileged accounts.
  • Make sure you have reviewed and configured external sharing for SharePoint and OneDrive, and Teams.
  • Make the checking of the Security Score and Identity Secure Score part of your regular IT monthly checkups. Make sure to mark tasks to move these tasks into an appropriate status, e.g., Planning, Done, etc.

Security and Identity Secure score

  • Make sure auditing is enabled today!
  • Should you need longer retention of Office 365 audit logs, consider 3rd party tool options.
  • Every user connecting to Office 365 should have MFA enforced.
  • Deploy a custom, branded login page for Office 365.

In phase two:

  • Conduct an inventory of services, owners, and admins.
  • Identify Microsoft accounts in administrative roles that you need to switch to work or school accounts.
  • Ensure separate user accounts and mail forwarding for global administrator accounts.
  • Make sure you change the passwords of administrative accounts.
  • Turn on password hash synchronization.
  • Require multifactor authentication (MFA) for users in all privileged roles as well as exposed users.
  • Configure Identity Protection.
  • Obtain your Office 365 Secure Score.
  • Review the Office 365 security and compliance guidance.
  • Establish the owners of the incident/emergency response plan.
  • Secure on-premises privileged administrative accounts.
  • Complete an inventory of subscriptions.
  • Remove Microsoft accounts from admin roles.
  • Monitor Azure activity.
  • Configure conditional access policies.

That’s it from me and I hope you will find my tips useful. Want to read more posts from us? Subscribe to our blog and stay updated.

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