How to check if it was hacked?
 

Hello, I am running the 3.8.3.

In the same hosting I have some blogs. Some of them got hacked and I have cleaned them, changed credentials and so forth...

I am still getting "":fail: Domain mydomain.net has exceeded the max emails per hour (500) allowed. Message discarded."" when trying to send emails.
[the problem is that these php script mails are not sent by me, and the visitors I have are too few in order to generate so many emails]

I am now starting to think that maybe there is some problem also in the forum... is there any tool that analyzes the files for me, or should I go ahead and check some of the main files manually?

Thank you