Hello,
Adaxes uses AD LDS / ADAM as its backend server. Adaxes configuration data, and in particular custom properties, are stored on the Adaxes backend. As to answers to Security Questions, we do not store them. We store only a hash of each answer, which is also stored on Adaxes backend. The only user who can access this information is Adaxes default service administrator (the user that you specified during Adaxes installation). If you have several services that share common configuration, then all default service administrators of all these Adaxes services will have access to the data stored on the Adaxes backend.