When setting up a Windows service, one specifies a user account to use for authentication, as well as the password for that user. In their guidelines for user account selection, Microsoft states that when using a domain user account,
Be aware that even though the service control manager (SCM) stores the password in a secure portion of the registry, it is nevertheless subject to attack.
They make no mention of what such an attack would look like. I assume that one would want to have administrative privileges on the OS hosting the service, and it would seem that the password is only used when the service is started, so that restarting it could play a role.
So, the question is: What does Microsoft mean when they say that a domain user's password is subject to attack? And, are there any substantial differences between the (more recent) versions of the OS?