前言
文件上传漏洞靶场Upload-labs，在github上下载后部署在win10本地，php版本为5.2.17，测试环境使用Kali虚拟机
https://github.com/c0ny1/upload-labs
Pass-01
首先尝试上传一句话木马up.php文件发现上传失败，并提示只允许.jpg|.png|.gif类型，但是我们的burp并没有抓到这个包，于是判断此处的限制为前端验证，我们直接查看源代码
将此处判断文件类型的语句修改，即可正常绕过前端验证
成功上传后界面出现了刚刚上传的图片，由于上传的是php文件，所以无法正常解析成图片
右键点击复制图像地址即可得到文件上传的路径，在蚁剑中直接连接
Pass-02
先尝试能否直接上传up.php，提示文件类型不正确
我们在抓到的包中尝试修改Content-Type为image/jpeg，继续上传
成功上传，复制路径后蚁剑连接
Pass-03
上传up.php后提示不允许以上后缀，我们尝试后缀改写绕过，将php改写为php5，成功上传，依旧可以被解析为php
（此处与不同环境的apache配置文件有关，配置文件中需要有下面这句话才可以成功）
AddType application/x-httpd-php .php .phtml .phps .php5 .pht
Pass-04
本题使用以上几种方法均无法上传up.php，黑名单过滤的十分严密，基本只允许上传图片格式，但值得注意的是，黑名单中并没有.htaccess，于是我们可以选择上传.htaccess文件，既然只允许上传jpg文件，我们就上传jpg格式的一句话，再利用我们上传的.htaccess将jpg解析为php，构造如下文件
再直接上传jpg格式的一句话，并用蚁剑连接
Pass-05
本题相当刁钻，黑名单包括转换，大小写，空格，还有点号，几乎所有php文件都上传不了，并且拒绝上传 .htaccess 文件，源代码如下
$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");
$file_name = trim($_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
$file_ext = str_ireplace('::$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！';
}
}
黑名单中没有的后缀名有 .php7 以及 .ini，此处应该使用 .user.ini解析漏洞，思路和.htaccess有些相似
使用 .user.ini 解析漏洞需要三个前提条件：
①服务器后端语言为php
②文件上传目录中有可利用的php文件
③服务器使用CGI／FastCGI模式
这个漏洞非常少见，限制条件也很多，感觉实战中并不好用
本关的提示为上传目录存在readme.php，可以利用这个php文件
我们先上传一个图片格式的一句话木马
再构造.user.ini如下，使目录下所有php文件都包含up.jpg，从而将恶意代码注入上传目录中已经存在的可利用php文件中
根据提示可知，目录下有readme.php，我们输入该文件的地址即可连接
Pass-06
直接大小写绕过
Pass-07
$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', '', $file_ext);//去除字符串::$DATA
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 = '此文件不允许上传';
}
} else {
$msg = UPLOAD_PATH . '文件夹不存在,请手工创建！';
}
}
源代码没有去掉空格，直接在文件名末尾加空格绕过黑名单
（Linux不可以，只有在windows下能成功）
Pass-08
和上一题类似，本题没有去掉文件名末尾的点，故抓包后文件末尾加点绕过
Pass-09
源代码中没有去掉::$DATA，抓包在文件末尾加上后可绕过检测，但解析时会忽略::$DATA
Pass-10
$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
$file_ext = str_ireplace('::$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！';
}
}
本题源码中能过滤的都过滤了，但可以知道deldot只会删除末尾的一个点，
故可以构造文件后缀php. .
Pass-11
$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","jsp","jspa","jspx","jsw","jsv","jspf","jtml","asp","aspx","asa","asax","ascx","ashx","asmx","cer","swf","htaccess","ini");
$file_name = trim($_FILES['upload_file']['name']);
$file_name = str_ireplace($deny_ext,"", $file_name);
$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 = UPLOAD_PATH . '文件夹不存在,请手工创建！';
}
}
本题源代码中str_ireplace会将黑名单中的函数替换为空，故双写绕过
