source: https://www.securityfocus.com/bid/13433/info

PHPCoin is reportedly affected by multiple SQL injection vulnerabilities. These issues are due to a failure in the application to properly sanitize user-supplied input before using it in SQL queries.

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/login.php?w=user&o=login&phpcoinsessid=SQL_INJECTION'