Symptoms

Many email messages are being sent from PHP scripts on the server. How can I find the domains on which these scripts are running if I am using Postfix?

Resolution

Note: This article is for Postfix. If you are using the Qmail mail server, see article
1711: Many email messages are sent from PHP scripts on the server. How can I find the domains on which these scripts are running?

There is a way to determine from which folder the PHP script that sends mail was run.

Note: Depending on your operating system and Plesk version, the paths can differ slightly from those listed below.

1. Create a /usr/sbin/sendmail.postfix-wrapper script with the following content:

   Create a file and open it for editing:

   #touch /usr/sbin/sendmail.postfix-wrapper
   #vi /usr/sbin/sendmail.postfix-wrapper
   

   Add the following content:

   #!/bin/sh
   (echo X-Additional-Header: $PWD ;cat) | tee -a /var/tmp/mail.send|/usr/sbin/sendmail.postfix-bin "$@"
   

   Note that this should be two lines, including #!/bin/sh.

2. Create a log file, /var/tmp/mail.send, and grant it a+rw rights. Make the wrapper executable, rename the old sendmail, and link it to the new wrapper. Then run the commands below:

   ~# touch /var/tmp/mail.send
   ~# chmod a+rw /var/tmp/mail.send
   ~# chmod a+x /usr/sbin/sendmail.postfix-wrapper
   ~# mv /usr/sbin/sendmail.postfix /usr/sbin/sendmail.postfix-bin
   ~# ln -s /usr/sbin/sendmail.postfix-wrapper /usr/sbin/sendmail.postfix
   

3. Wait for an hour and change the sendmail back:

   ~# rm -f /usr/sbin/sendmail.postfix
   ~# mv /usr/sbin/sendmail.postfix-bin /usr/sbin/sendmail.postfix
   

Check the /var/tmp/mail.send file. There should be lines starting with X-Additional-Header: pointing to the domain folders where the scripts that sent the mail are located.

You can see all the folders from which mail PHP scripts were run with the following command:

    ~# grep X-Additional /var/tmp/mail.send | grep `cat /etc/psa/psa.conf | grep HTTPD_VHOSTS_D | sed -e 's/HTTPD_VHOSTS_D//' `

NOTE: If you see no output from the above command, it means no mail was sent using the PHP mail() function from the Plesk virtual hosts directory.

Usually, that means one of the mail accounts has been compromised. Check the login attempt count:

# zgrep -c 'sasl_method=LOGIN' /usr/local/psa/var/log/maillog*
/usr/local/psa/var/log/maillog:221000
/usr/local/psa/var/log/maillog.processed:362327
/usr/local/psa/var/log/maillog.processed.1.gz:308956

If you see an unusually high number of login attempts, it is very likely accounts were compromised. You can try identifying these accounts in the following way:

# zgrep 'sasl_method=LOGIN' /usr/local/psa/var/log/maillog* | awk '{print $9}' | sort | uniq -c | sort -nr | head
891574 [email protected]

To stop spam from being sent, change passwords for the compromised accounts and restart the Postfix service.

For Plesk 12 also visit Administrator’s Guide page