Unfortunately, someone managed to crack one of my email accounts, and have been using my mailserver to send out a lot of spam.
This was discovered about 10-11 hours after they gained access to the account and was remedied shortly after it was discovered. The mailserver was shutdown while the mailqueue was deleted (some thousands spam-mails that were still to be sent) and all passwords on the system changed.
The server was scanned for any backdoors, and to the best of my knowledge, no backdoors had been created.
The incident was caused by someone who managed to bruteforce what I considered to be a strong password, and therefore they was able to authorize them selves to send mail from my server. As mentioned above, all passwords on e-mail accounts and the server it self have been changed to more secure passwords. This will hopefully not be bruteforced again, but as computing power becomes cheaper and the spammers earn money by baiting/phishing for more money in the e-mails they send, nothing is certain.
If you have received spam from my domain, I’m sorry, and I have taken the necessary precautions to make sure it will not be as easy for someone else to gain access to the mail server again.