source: http://www.securityfocus.com/bid/13834/info

NEXTWEB (i)Site is prone to 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. 

Supplying the following is sufficient to gain access to the admin control panel:
username: admin
password: ' or 'a'='a