"kcproxy wants to make changes" - but I am the administrator or not?

When I tried to view the System PW, I got a pop up window "kcproxy wants to make changes. Enter an administrator's name and password to allow. kcproxy wants to use the "System" keychain".

I learned that this is part of Keychain Access that runs when you use a non-administrator account.

I am the only administrator, there is not even another user. If I type in my user name and password I am able to see the password.

In users and groups only I am listed as admin, no other users. How can I find out if there is a hidden administrator?

I noticed in the system keychain entries with NETHERLANDS VPN (VPN Password and IPSec Shared Secret), that have been modified today. I do not use a VPN. I don`t know how and when NETHERLANDS VPN got into the system keychain. The system keychain also contains a lot of false entries like three times iphone with my name and wrong passwords.