upload-labs第九关教程

一、源代码分析
- 代码审计
- ::$DATA介绍
二、绕过分析
- 特殊字符::$data绕过
- - 上传eval.php
  - 使用burpsuite抓包进行修改
  - 放包，查看是否上传成功
  - 使用中国蚁剑进行连接

一、源代码分析

代码审计

$is_upload = false;
$msg = null;
if (isset($_POST['submit'])) {
    if (file_exists(UPLOAD_PATH)) {
        $deny_ext = array(".php",".php5",".php4",".php3",".php2",".html",".htm",".phtml",".pht",".pHp",".pHp5",".pHp4",".pHp3",".pHp2",".Html",".Htm",".pHtml",".jsp",".jspa",".jspx",".jsw",".jsv",".jspf",".jtml",".jSp",".jSpx",".jSpa",".jSw",".jSv",".jSpf",".jHtml",".asp",".aspx",".asa",".asax",".ascx",".ashx",".asmx",".cer",".aSp",".aSpx",".aSa",".aSax",".aScx",".aShx",".aSmx",".cEr",".sWf",".swf",".htaccess",".ini");
        $file_name = trim($_FILES['upload_file']['name']);
        $file_name = deldot($file_name);//删除文件名末尾的点
        $file_ext = strrchr($file_name, '.');
        $file_ext = strtolower($file_ext); //转换为小写
        $file_ext = trim($file_ext); //首尾去空
        
        if (!in_array($file_ext, $deny_ext)) {
            $temp_file = $_FILES['upload_file']['tmp_name'];
            $img_path = UPLOAD_PATH.'/'.date("YmdHis").rand(1000,9999).$file_ext;
            if (move_uploaded_file($temp_file, $img_path)) {
                $is_upload = true;
            } else {
                $msg = '上传出错！';
            }
        } else {
            $msg = '此文件类型不允许上传！';
        }
    } else {
        $msg = UPLOAD_PATH . '文件夹不存在,请手工创建！';
    }
}

相对于上面的关卡来说，它少了对::$DATA的过滤，所以是不是可以考虑通过::$DATA进行绕过

::$DATA介绍

备用数据流（Alternate Data Streams，ADS）是Windows中的一个特性，它允许在一个文件中隐藏额外的信息。这个特性是NTFS（Windows常用的一种文件系统）独有的。
可以这样想：可以把备用数据流想象成一本书中的“隐形笔记”。这本书（文件）看起来还是那本书，里面的主要内容没有变，但你可以在书页的空白处（备用数据流）用隐形墨水写一些额外的内容（数据流），只有知道方法的人才能看到这些内容。