Recently we started getting spam complaints for mails that were sent from our server, obviously not deliberately.
Now since we have a whole bunch of sites running on our server, finding out which one was hacked, promised to be a tedious job.
Until… we found this post : How To Log Emails Sent With PHP’s mail() Function To Detect Form Spam
This script will write out all sites using the PHP sendmail function into a log file, making it very easy to find out where the spam is coming from.
It saved us from a very very long night!
We have put the whole content of the wonderful article by till on our blog and made some minor modifications to the explanation.
Hope it helps!
1 Installing the wrapper script
Create a new file that will contain the script:
touch /usr/local/bin/phpsendmail
Use nano, vi or your favorite text editor to edit the file you just created and enter this script:
#!/usr/bin/php
<!--?php
/**
This script is a sendmail wrapper for php to log calls of the php mail() function.
Author: Till Brehm, www.ispconfig.org
(Hopefully) secured by David Goodwin <david @ _palepurple_.co.uk-->
*/
$sendmail_bin = '/usr/sbin/sendmail';
$logfile = '/var/log/mail_wrapper.log';
//* Get the email content
$logline = '';
$pointer = fopen('php://stdin', 'r');
while ($line = fgets($pointer)) {
if(preg_match('/^to:/i', $line) || preg_match('/^from:/i', $line)) {
$logline .= trim($line).' ';
}
$mail .= $line;
}
//* compose the sendmail command
$command = 'echo ' . escapeshellarg($mail) . ' | '.$sendmail_bin.' -t -i';
for ($i = 1; $i < $_SERVER['argc']; $i++) {
$command .= escapeshellarg($_SERVER['argv'][$i]).' ';
}
//* Write the log
file_put_contents($logfile, date('Y-m-d H:i:s') . ' ' . $_ENV['PWD'] . ' ' . $logline, FILE_APPEND);
//* Execute the command
return shell_exec($command);
?>If you use a different Linux distribution than Debian, the sendmail binary might be in a different location than /usr/sbin/sendmail and you have to change the sendmail path in the line $sendmail_bin = ‘/usr/sbin/sendmail’; of the script.
Now make the script executable…
chmod +x /usr/local/bin/phpsendmail
… and create the logfile and make it writable:
touch /var/log/mail_wrapper.log
chmod ugo+w /var/log/mail_wrapper.log
2 Modifying the php.ini
Now we reconfigure PHP so that it uses our wrapper script to send the emails.
Open the php.ini file…
vi /etc/php5/apache2/php.ini
… and uncomment the sendmail_path line and put the path to the script we created
; For Unix only. You may supply arguments as well (default: "sendmail -t -i").
sendmail_path = /usr/local/bin/phpsendmail
If you use php as cgi, with suphp or as fcgi, then change the same lines in the file /etc/php5/cgi/php.ini, too.
Restart the Apache webserver to apply the changes.
/etc/init.d/apache2 restart
3 Test the setup
To test this setup, create a new php file with the name mailtest.php in one of your websites with the content:
Then open the file in a webbrowser to execute it. The test message should be logged now into the logfile. Check this with the command:
cat /var/log/mail_wrapper.log
Off course, don’t forget this wonderful command:
tail -f /var/log/mail_wrapper.log
