That's all normal activity (failed logins) for any internet facing
machine. They may be dictionary attacks, or not... If they get on your
nerves, block them. Strong passwords will help more.
Also, it's likely that you have forged mail coming in from outside, and
not really "spam from local users" ?
If it is really locally generated, then disable the account.
Ken
On 9/9/2011 4:45 PM, Nikos Papadopoulos wrote:
Hello,
I am using Dovecot ver.1.0.7 on an x86 server with RedHat Linux Enterprise 5
and the following configuration:
# 1.0.7: /etc/dovecot.conf
protocols: pop3
login_dir: /var/run/dovecot/login
login_executable: /usr/libexec/dovecot/pop3-login
mail_location: mbox:~/mail:INBOX=/var/mail/%u
mail_executable: /usr/libexec/dovecot/pop3
mail_plugin_dir: /usr/lib/dovecot/pop3
pop3_client_workarounds: outlook-no-nuls oe-ns-eoh
auth default:
passdb:
driver: pam
userdb:
driver: passwd
It seems that my mail server is being attacked by someone who tries to
retrieve users' credentials. Please read below an output of logwatch.
dovecot-auth: pam_succeed_if(dovecot:auth): error retrieving information
about
user sandra
dovecot-auth: pam_succeed_if(dovecot:auth): error retrieving information
about
user tanya
dovecot-auth: pam_succeed_if(dovecot:auth): error retrieving information
about
user tanya
dovecot-auth: pam_succeed_if(dovecot:auth): error retrieving information
about
user dark
dovecot-auth: pam_succeed_if(dovecot:auth): error retrieving information
about
user dark
dovecot-auth: pam_succeed_if(dovecot:auth): error retrieving information
about
user gibson
dovecot-auth: pam_succeed_if(dovecot:auth): error retrieving information
about
user frank
dovecot-auth: pam_succeed_if(dovecot:auth): error retrieving information
about
user frank
Besides, some of the local users receive "spam" emails, which seem to be
sent by another local user.
Please assist me on how to prevent the aforementioned attack.
Best Regards,
Nikos
--
Ken Anderson
Pacific Internet - http://www.pacific.net
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