source: https://www.securityfocus.com/bid/14575/info
PersianBlog 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.
http://www.example.com/userslist.asp?page=2'&catid=16