Qmail user null & spam open

[Roberto Nunez]

Hello,
I can detect a lot of spam with Qmail, I have:

10:07:47 mail relaylock: /var/qmail/bin/relaylock: mail from 208.53.42.33:3140 (not defined)
10:07:48 mail smtp_auth: SMTP connect from (null)@(null) [208.53.42.33]
10:07:48 mail smtp_auth: smtp_auth: SMTP user postmaster : logged in from (null)@(null) [208.53.42.33]

The issue appear for others accounts, How is possible that connect from null???

Is it a database issue, Qmail, other?

This issue is a big open door for spammer.

CentOS 5.4 - Plesk 9.5.1

Thanks for any suggest.

 

[IgorG]

Did you tried to rebuild mailsettings with mchk? Did you checked system with chkrootkit, rkhunter?

 

[Roberto Nunez]

Did you tried to rebuild mailsettings with mchk? Did you checked system with chkrootkit, rkhunter?

Hi Igor,
Yes, I tried rkhunter and chkrootkit with goods results. Is normal mail smtp_auth: SMTP connect from (null)@(IP) [208.53.42.33]??

Thanks!