Server hacked 1

[coolmatt]

Hi,

I run a little site on a VPS (CentOS) and my own mail server (Postfix) as well.
For months, everything went smoothly, until the impossible (over confident, I know) : one of my email accounts was flooded with undelivered mail notifications. The postfix log confirmed it : thousands of mails were sent. I immediatly changed the password, but this had no effect and I am still officially a spammer :-(

The problem is, although I managed to install and configure my server, security is a topic beyond my knowledge (I am software programmer)... so any help/tips are welcome... where do I start looking ?

Regards,
matt

 

[ChrisHirst]

https://linux-audit.com/postfix-hardening-guide-for-security-and-privacy/

Chris.

Indifference will be the downfall of mankind, but who cares?
Time flies like an arrow, however, fruit flies like a banana.

Never mind this jesus character, stars had to die for me to live.

 

[bluegroper]

This is another good thread for postifx on CentOS.

https://wiki.centos.org/HowTos/postfix

See especially the part/s about ensuring you're not an open relay.
HTH

 

[coolmatt]

Thank you