Now, first of all... I'm not sure if this is a problem with WHMCS or some other piece of software with a security hole, but I thought I should post here.
Our WHMCS got hacked earlier today and the hacker sent out a to be honest, unacceptable email to all clients, I won't go into detail but lets just say it directly insulted them.
Now apart from ruining our reputation and client relationships, I am now completely paranoid that it will happen again. I'd also like to know how it happened in the first place. The hacker signed up for a hosting account, and then sent the email. I have no idea how he/she did it, but when I look at the admin log in WHMCS, it shows the username "hacked" as logging in (see image).
Just a warning to everyone out there. His IP address was 86.132.228.82.