How to block proxy headers

Am wanting to block these proxyheader attempts to prevent spam usage from outside sources. They are constantly coming up in my log files.


http://98.126.15.13/proxyheader.php: 1 Time(s)
http://aruu.info/proxyme.php: 1 Time(s)
http://www.cjpjp.com/proxyheader.php: 1 Time(s)
http://www.mtajp.com/proxyheader.php: 1 Time(s)
http://www.quickebuy.com/505.php: 1 Time(s)
http://www.racross.com/proxyheader.php: 1 Time(s)
http://www.travelimgusa.com/ip.php: 1 Time(s)

Can anyone show me how to block these types of attempts?

 

//PHPMYADMIN/config/config.inc.php?p=phpinfo();: 4 Time(s)
//admin/config/config.inc.php?p=phpinfo();: 4 Time(s)
//config/config.inc.php?p=phpinfo();: 4 Time(s)
//dbadmin/config/config.inc.php?p=phpinfo();: 4 Time(s)
//mail/config.inc.php?p=phpinfo();: 4 Time(s)
//myadmin/config/config.inc.php?p=phpinfo();: 4 Time(s)
//mysql/config/config.inc.php?p=phpinfo();: 4 Time(s)
//php-my-admin/config/config.inc.php?p=phpinfo();: 4 Time(s)
//phpMyAdmin/config/config.inc.php?p=phpinfo();: 4 Time(s)
//phpMyAdmin2/config.inc.php?p=phpinfo();: 4 Time(s)
//phpmyadmin/config/config.inc.php?p=phpinfo();: 4 Time(s)
//phpmyadmin2/config.inc.php?p=phpinfo();: 4 Time(s)
//phppgadmin/config.inc.php?p=phpinfo();: 4 Time(s)
//pma/config/config.inc.php?p=phpinfo();: 4 Time(s)
//webmail/config.inc.php?p=phpinfo();: 4 Time(s)
/robots.txt: 1 Time(s)
/webdav/: 6 Time(s)
http://healthiwant.com/proxyheader.php: 2 Time(s)
http://ppcfinder.net/judge.php: 1 Time(s)
http://www.bankjia.com/ip.php: 1 Time(s)
http://www.eduju.com/proxyheader.php: 1 Time(s)
http://www.shopsline.com/proxyheader.php: 1 Time(s)


these sort of attacks are becoming very popular in the weekly logwatch.

Has anyone any idea to defend against these sort of attacks?