Do you mind me asking how you know the email accounts are/have been hacked
Firstly, do you have BFD installed, if not I would advise you do
Have you checked your mail que and if you view, you should see where it has been generated from ie website or email account - take note of email address and domain. This may help you narrow to domains
If some of your clients IP address are listed in RBL?s, are you sure the email is not simply been declined due to RBL listing of their IP address.
Have you checked your own sending IP address used by qmail. If listed, again this may indicate where to start looking
Do you have maldet installed, updated and running. If so, run a manual scan on /home /opt /tmp/vat/tmp directories. Please make sure clamAV is fully updated as maldet will make use of clamAV
There?s probably more but if you could update re above
tha hacker are getting my customers email password, sou i only can detect them when my qmail is high , i change the password to the hack account
i dont have BFD install becouse when i change the password to an email account the rest of my client network gets block and the problem gets worst.
my clients ip have small problems when thay are in RBL , my servers sometimes get on RBL becouse of the hack emails
i have never use maldet i will install it, how do you update manually clamav , i have tried some commands and i think clamav isent updateing.
i am want to determine if the email server is hack somehow or if there is a vulnerability i have not consider.
At the moment i am running a script to determine if the qmail is high i stop de smtp out and send a warnning, i go in and change the password to the hack email account
ClamAV should auto update, just login to nodeworx, server, logs, mail, freshclam to check current update
You could look at spamdyke which may help
To be honest, rereading your posts, I am inclined to think the issue maybe at your clients computer, as given you have reset password and it runs normally then starts again. This may explain why the password is known - directly at clients computer
It?s just a thought as I would need more details to help further (sample of email, header details etc…)