Vulnrability in myPHPnuke 1.8.8

[Lifo Fifo <lifofifo20@xxxxxxxxx>]

Language : PHP
Script : http://www.myphpnuke.com 1.8.8 
Problem : SQL Injection
Description : myphpnuke is a widely used Content Managemnt System.

Problem :

In auth.inc.php file,

*********************
if ((isset($aid)) && (isset($pwd)) && ($op == "login")) {
if($aid!="" AND $pwd!="") {
$q="select pwd from ".$mpnTables['authors']." where aid='$aid'";
$result=mysql_query("select pwd from ".$mpnTables['authors']." where 
aid='$aid'");
list($pass)=mysql_fetch_row($result);
if ($pass == $pwd) {
$pwd1 = md5($pwd);
mysql_query("update ".$mpnTables['authors']." set pwd = '$pwd1' where 
aid='$aid'");
$pass = $pwd1;
} else {
$pwd1 = md5($pwd);
}
if($pass == $pwd1) {
$admin = base64_encode("$aid:$pwd1");
setcookie("admin", "$admin", time()+2592000, "", "", ""); // 1 mo is 2592000
}
}
}
********************

Here the $aid is not checked. If you open the page like,

Therefore you can run the query like,

select pwd from mpn_authors where aid='mad' into outfile '/filepath/file.txt'

when you enter 
aid=mad' into outfile '/filepath/file.txt

This will not work if magic_quotes_gpc is on.

Fix : 

Find the line
**********
if ((isset($aid)) && (isset($pwd)) && ($op == "login")) {
if($aid!="" AND $pwd!="") {
**********

Add

**********
$aid=addslashes($aid);
**********

Credit :
lifofifo & hackingzone.org