My recent talk at the great T2 conference on DoSing Azure AD gained a lot of attention. Unfortunately, the talk was not recorded, so I decided to write a blog for those who couldn’t attend. So here we go!

Devices (endpoints) are a crucial part of Microsoft’s Zero Trust concept. Devices can be Registered, Joined, or Hybrid Joined to Azure AD. Conditional Access uses the device information as one of the decisions criteria to allow or block access to services.

In this blog, I’ll explain what these different registration types are, what happens under-the-hood during the registration, and how to register devices with AADInternals v0.4.6.

In October 2020, someone contacted me and asked whether it would be possible to create BPRTs using AADInternals. I hadn’t even heard of BPRTs, but was eventually able to help him to create BPRTs. Now this functionality is included in AADInternals v0.4.5.

In this blog, I’ll explain what BPRTs are and how they can be used to join multiple devices to both Azure AD and Intune. I’ll also show the dark side of BPRTs: how they can be used to conduct DOS attacks against Azure AD, and how to detect and prevent this.