title: How to find out which code is using Sendmail?
body: <p>We are having some unknown code (virus?) sending out thousands of mails from our server suddenly and though we think we have removed the corresponding malicious PHP file, the mails are still getting sent out. </p>
  
  <p>How can I find out which code is sending out the mails? I tried looking under /var/log/maillog but no pointers there. Any other way of finding it out?  </p>
  
  <p>We are using CentOS distro. </p>