I am a bit surprised by this thread.
Here is a user who has concluded that his SME Server has been compromised by hacker attack.
Isn't security one of the key strengths of SME Server?
lucaegloff - do you have any idea how this breach of your server occurred?
Which apps are you running and
are they up-to-date (ref. Stefano's suggestion)?
Are you using "very good passwords" (ref. CharlieBrady's suggestion)?
Disable ssh access whenever possible. Use RSA keys for authentication, in preference to passwords
Charlie, for clarification - are you suggesting that SSH access be disabled totally (WAN and LAN), or only from WAN-side. Also, I am assuming that you are saying that
if you have to use SSH from WAN then strongly suggest RSA-keys for authentication.
Is SSH (RSA-key authentication) the most secure/robust option that SME-users now have for remote access?
By the way, I came across this website that explains very well 'password strength' for anyone interested:
https://www.grc.com/passwords.htmhttps://www.grc.com/haystack.htm