The contents and solution to this problem may seem obvious, but it wasn’t to me, so I decided to write about my research, in-case I’m not alone. If you didn’t notice the repetition of the word “THE” in the header image above, you too may have missed the blindingly obvious which I discuss below! The problem When developing an OS X kernel extension (kext), it is sometimes a requirement that we develop a user-land application in tandem, in order to control the tasks performed in the kext, or receive notifications from the kernel.

As a software engineer working in the field of security, I needed to know if a user was that of the local machine, or a user authenticated by Active Directory. The way in which accounts (users and groups) are identified by macOS(or Unix variants) differs from those under Windows Windows associates a user account with a Security Identifier (SID), along with a user’s credentials; name and password. In contrast, macOS is all about the uid (user id) and gid (group id), as is well known to those also familiar with Linux.