[Exim] Server hacked....

Hello All,

From last few days the server load is continuously running between 25% -
75%. Someone has hacked into the server sending mail. Is there some way we
can tract this and shut them out.

6166 root 0 3.2 0.5 sendmail
6173 root 0 3.2 0.5 sendmail
6175 root 0 3.0 0.5 sendmail
6180 root 0 3.0 0.5 sendmail
6187 root 0 3.0 0.5 sendmail
6163 root 0 2.9 0.5
/usr/sbin/exim-MCS-MCP-MCremote_smtpmx2.mail.yahoo.com219R55Q-0003AL-00
6182 root 0 2.9 0.5 sendmail
6190 root 0 2.9 0.5
/usr/sbin/exim-MCS-MCP-MCremote_smtpmx2.mail.yahoo.com219R55R-0003AU-00
6194 root 0 2.7 0.5
/usr/sbin/exim-MCS-MCP-MCremote_smtpmx2.mail.yahoo.com219R55P-0003AE-00
5595 nobody 0 2.5 3.8 httpd
6155 root 0 2.5 0.5 sendmail
6186 root 0 2.5 0.5
/usr/sbin/exim-MCS-MCP-MCremote_smtpmx2.mail.yahoo.com219R55T-0003Al-00
6158 root 0 2.3 1.0
/usr/sbin/exim-MCS-MCP-MCremote_smtpmx2.mail.yahoo.com219R55S-0003AZ-00
6160 root 0 2.3 0.5 sendmail
6165 root 0 2.3 0.5
/usr/sbin/exim-MCS-MCP-MCremote_smtpmx1.mail.yahoo.com219R55V-0003At-00


Thank you,