MSSPs and Identity: Q&A

TL;DR – Follow-up to the previous blog post to answer common questions

After I published the last blog post on MSSPs and Identity, I received various questions, and I thought it would be useful to answer the most common ones via this follow-up post. Let’s jump right in!

What is the difference between delegating access for Sentinel and/or Defender for Cloud (MDC) vs delegating access for Microsoft 365 Defender?

As I shared on previous posts, you can delegate access to Sentinel and to MDC using Azure Lighthouse. For the list of Azure subscription level roles, please reference the Azure built-in roles. But you cannot use Azure Lighthouse to delegate access for Microsoft 365 Defender. That’s because both Sentinel and MDC have permissions at Azure subscription level, whereas Microsoft 365 Defender has permissions at tenant level. In the diagram below, the Microsoft 365 Defender roles exist in the dark blue area, which is tenant level, while the Sentinel and MDC roles exist in the light blue area, which is subscription level.

For the list of tenant level roles, please reference the Azure AD built-in roles. As an MSSP, your customers can grant you access to their Microsoft 365 Defender tenants using either B2B or GDAP.

What is the difference between B2B and GDAP?

There are probably quite a few differences, but the one that MSSPs probably care the most about is that B2B collaboration users are represented in the customer’s directory, typically as guest users. Some partners have compliance requirements that do not allow that type of configuration. Luckily, in the case of GDAP, there is no guest user in the customer’s tenant. However, customers can still view sign-ins from partners by querying for ‘Cross tenant access type: Service provider‘, as shown below.

Also, GDAP is configured via Partner Center, so it’s exclusively for partners that are Cloud Solution Providers (CSPs). There is a great document that includes security best practices for CSPs, I highly encourage partners to review those. I especially encourage partners to take advantage of the free Azure AD P2 subscription.

Personally, I use B2B for all my testing because I don’t have access to Partner Center. If, like me, you are working on a POC, B2B is a good option to simulate the behavior. Furthermore, if you are working on a POC, I recommend you try a new feature called cross-tenant synchronization, which is in public preview currently. It allows me to automatically provision users to my customer tenants (as guests) without having to invite them. With the configuration I am using, I just add them to a group, i.e. ‘SOC team’, and then that triggers the provisioning to the target tenant (customer tenant). Again, this is good for POCs, I would not recommend this for production scenarios.

What happens when my SOC team is working on an incident in Sentinel and there’s a link to the Microsoft 365 Defender alerts? How does it know which customer tenant the incident is associated with?

If you hover over the link in Sentinel, you’ll notice that it includes a tid (tenant id) value in the URL.

So, when you click on the link, you are redirected to the correct incident for the correct customer, as shown below. This will work as long as your user has been granted the necessary access on that tenant via B2B or GDAP.

I noticed the MDC documentation references a Security Admin, is that the same as the Security Administrator for Microsoft 365 Defender?

No, the Security Admin that grants permissions to MDC (and Defender for IoT) is at subscription level, whereas the Security Administrator that grants permissions to Microsoft 365 Defender is at tenant level.

Does Azure Lighthouse allow a customer to delegate access to two different partners (or tenants)?

Yes! I get this question because some partners have different tenants for users that are managing customer resources for different reasons. For example, there may be an MSSP tenant that just exists to manage security for customers and there may be a different tenant that exists to manage non-security services. In that case, partners may need to configure access for one customer but delegate different levels of access to different tenants. And, yes, it works as expected. It will just show as two different offers, as shown below:

Do I need a separate subscription for Sentinel?

A separate subscription is recommended for the Microsoft Sentinel workspace, and the main reason is permissions. If you think about it, this subscription will include very privileged data, so you want to implement tight controls over which users can access and make changes to the resources in the security subscription.

Can a partner create a subscription for a customer?

As a CSP, partners can create a subscription for their customers. Keep in mind, this subscription will still need to be associated with the customer’s tenant. This is very important. The billing of the subscription can be via the partner, which is possible for CSPs. However, the tenant associated with that subscription still needs to be the customer’s tenant. This is important because you have certain features, like ingestion of Microsoft Defender 365 data, UEBA, etc. that will need to be configured for that customer tenant. As you know, the data is always ingested into the customer’s subscription.

A customer can have any number of subscriptions associated with their main tenant and not all of them need to be billed in the same manner. That means, you can have a customer with 25 subscriptions associated with their tenant and the customer can be billed directly for 24 of those subscriptions, and one can be billed via the partner, as a CSP.

Is Microsoft 365 Lighthouse an option for MSSPs to gain access to Microsoft 365 Defender?

Microsoft 365 Lighthouse is a solution specifically for managing small- and medium-sized business (SMB) customers. CSPs will need to configure GDAP prior to onboarding customers to Microsoft 365 Lighthouse. It allows CSPs to manage some features within Microsoft 365 Defender and take certain actions. Please check the list of requirements, including the limit on the size of the tenant, which at the time of writing this blog is 2500 licensed users.

That’s it for now!

I hope these answers are useful. Keep those questions coming! As always, if I don’t know the answer, I’ll go find out and then we’ll both learn. 🙂

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