文件上传复习（upload-labs 6-13关）

Pass-06（大小写绕过）

$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 = 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.'/'.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！';}
}

查看代码，发现又限制了好多后缀名

但是没有禁止phP 、Php，所以尝试将文件后缀大小写绕过限制

2005.Php

<?php
phpinfo();
?>

发现上传成功

注意：这里php版本选非nts版本的才能成功

Pass-07（空格绕过黑名单）

$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 = $_FILES['upload_file']['name'];$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 = str_ireplace('::$DATA', '', $file_ext);//去除字符串::$DATAif (!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 = '此文件不允许上传';}} else {$msg = UPLOAD_PATH . '文件夹不存在,请手工创建！';}
}

阅读代码发现缺少了首尾去除空格的代码过滤

利用PHP 和 Windows环境的叠加特性 windows系统自动删除文件名后缀的空格绕过黑名单

所以我们上传.php文件进行抓包，然后在.php后面加上一个空格，这样我们上传的就是.php文件

然后直接放行

访问url，发现上传成功了

Pass-08（点绕过黑名单）

$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！';}

查看代码，

和第七关同理获取的最终文件后缀为“.” 不在黑名单里面

利用Windows系统保存文件的特性会删除文件后缀名的xxx.php. 最后上传的文件还是xxx.php

所以直接抓包，然后在.php后面加上“.”

直接访问上传的文件的url，上传成功

Pass-09（::$DATA绕过黑名单）

查看代码，发现这一关黑名单没有对::$DATA 进行处理使用::$DATA 进行处理，可以使用::$DATA绕过黑名单

补充知识：php在window的时候如果文件名+"::$DATA"会把::$DATA之后的数据当成文件流处理,不会检测后缀名，且保持"::$DATA"之前的文件名

做法和前两关差不多，就是抓包后在.php文件后面加上“::$DATA”

但是访问url是发现报错回显：

注意访问路径中不含::$DATA

即可成功访问

在网址栏中删掉“::$DATA”后再进行访问，发现上传成功

Pass-10（点空格点绕过黑名单）

用.php. .绕过

我这里用 2005.php. .绕过

代码运行最后得到的后缀为"." 不在黑名单中然而又用原来的2005.php. .来保存文件由于windows在

文件命名中会自动删除.和空格所以最终得到的是2005.php 因此绕过了黑名单限制

上传成功

Pass-11（双写php绕过黑名单）

现依旧是用上传的文件名来拼接路径并保存文件没有对文件重命名

只是用了str_ireplace()函数来检测（此函数无视大小写）如果文件名含有黑名单里面的字符串就替换为空

但是只替换一次并没有进行正则匹配或者是循环匹配敏感字符因此只要双写php即可因为是从左往右读的所以替换为空后还是php

所以pphphp、phphpp都可以尝试

这里我上传的是后缀为.pphphp文件，上传成功了

Pass-12（%00截断白名单）

本关提示：本pass上传路径可控！

代码漏洞点就在于用$_GET['save_path']来组成上传的文件路径而这个get传参是我们可以控制的地方

因此我们考虑用是否能进行截断例如形成../upload/12.php/截断后面的(xxx.jpg)

这样就通过了白名单校验并且保存成了php文件

这里就要用到0x00截断的知识

url中的%00（只要是这种%xx）的形式，webserver会把它当作十六进制处理，

然后把16进制的hex自动翻译成ascii码值“NULL”,实现了截断burpsuite中16进制编辑器将空格20改成了00。

本质上来说，都是利用0x00是字符串的结束标识符，进行截断处理。

只不过GET传参需要url编码成%00而已

原理：php的一些函数的底层是C语言，而move_uploaded_file就是其中之一，遇到0x00会截断，0x表示16进制，URL中%00解码成16进制就是0x00。

%00的使用是在路径上！

重要的话说三遍。如果在文件名上使用，就无法正常截断了。如：aaa.php%00bbb.jpg

需要满足的条件

00截断的限制条件是PHP<5.3.29，且GPC关闭

因为当 magic_quotes_gpc 打开时，所有的 ' (单引号), " (双引号), \ (反斜线) and 空字符会自动转为含有反斜线的转义字符。

magic_quotes_gpc 着重偏向数据库方面，是为了防止sql注入，但magic_quotes_gpc开启还会对$_REQUEST, $_GET,$_POST,$_COOKIE 输入的内容进行过滤

直接上传.php文件，使用%00截断,然后抓包修改filename后面的文件后缀“.php”，将其改为“.jpg”

然后放包访问url