upload-labs 文件上传靶场 writeup
文件上传靶场练习
前言
文件上传漏洞是一个高危漏洞，想要复习一下，二刷一下文件上传靶场
Pass-01
提示：
本pass在客户端使用js对不合法图片进行检查！
通过提示发现是在客户端用js进行验证的，js验证实在发送到服务器端之前而验证的，那么我们就可以在此之前做点手脚。
可以先上传一个合法的文件，通过抓包来进行修改参数，就可以绕过这个限制了。
Pass-02
提示
本pass在服务端对数据包的MIME进行检查！
源码为：
$is_upload = false;
$msg = null;
if (isset($_POST['submit'])) {
if (file_exists(UPLOAD_PATH)) {
if (($_FILES['upload_file']['type'] == 'image/jpeg') || ($_FILES['upload_file']['type'] == 'image/png') || ($_FILES['upload_file']['type'] == 'image/gif')) {
if (move_uploaded_file($_FILES['upload_file']['tmp_name'], UPLOAD_PATH . '/' . $_FILES['upload_file']['name'])) {
$img_path = UPLOAD_PATH . $_FILES['upload_file']['name'];
$is_upload = true;
}
} else {
$msg = '文件类型不正确，请重新上传！';
}
} else {
$msg = UPLOAD_PATH.'文件夹不存在,请手工创建！';
}
}
在http数据包中，判断文件类型的是Content-Type字段的值
同样抓包，修改Content-Type为image/jpeg
就可以绕过判断
Pass-03
提示：
本pass禁止上传.asp|.aspx|.php|.jsp后缀文件！
通过提示可以看出，应该是不完善的黑名单所导致的漏洞。
使用不存在于黑名单但是可执行的后缀即可
常见的可执行文件的后缀：
PHP: php2、php3、php5、phtml、pht
ASP: aspx、ascx、ashx、cer、asa
JSP: jspx
注意：想要让服务器将你的文件解析为php，还需要将要修改httpd.conf：（把前面的#去掉）
AddType application/x-httpd-php .php .phtml .php3 .php4 .php5 .php2
Pass-04
提示：
本pass禁止上传.php|.php5|.php4|.php3|.php2|php1|.html|.htm|.phtml|.pHp|.pHp5|.pHp4|.pHp3|.pHp2|pHp1|.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后缀文件！
$is_upload = false;
$msg = null;
if (isset($_POST['submit'])) {
if (file_exists(UPLOAD_PATH)) {
$deny_ext = array(".php",".php5",".php4",".php3",".php2","php1",".html",".htm",".phtml",".pHp",".pHp5",".pHp4",".pHp3",".pHp2","pHp1",".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");
$file_name = trim($_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); //收尾去空
if (!in_array($file_ext, $deny_ext)) {
if (move_uploaded_file($_FILES['upload_file']['tmp_name'], UPLOAD_PATH . '/' . $_FILES['upload_file']['name'])) {
$img_path = UPLOAD_PATH . $_FILES['upload_file']['name'];
$is_upload = true;
}
} 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！';
}
}
这个黑名单就比较完善了，过滤了各种罕见后缀，但是没有过滤.htaccess
我们在.htaccess文件上写：
SetHandler application/x-httpd-php
意思就是把本目录下的jpeg文件当做php来解析
新建一个jpg文件，内容如下：
然后访问上传文件的存储位置，可以发现能够被解析为php文件。
Pass-05
$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",".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, '.');
$file_ext = str_ireplace('::$DATA', '', $file_ext);//去除字符串::$DATA
$file_ext = trim($file_ext); //首尾去空
if (!in_array($file_ext, $deny_ext)) {
if (move_uploaded_file($_FILES['upload_file']['tmp_name'], UPLOAD_PATH . '/' . $_FILES['upload_file']['name'])) {
$img_path = UPLOAD_PATH . '/' . $file_name;
$is_upload = true;
}
} 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！';
}
}
这个黑名单比前面的关卡更加完善了。过滤了.htaccess，但是代码中后缀转换为小写被去掉了，因此我们可以上传Php来绕过黑名单后缀。(在Linux没有特殊配置的情况下，这种情况只有win可以，因为win会忽略大小写)
Pass-06
查看提示发现同样是黑名店限制，几乎涵盖了所有危险的后缀，那么查看源码
$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",".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 = $_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, $deny_ext)) {
if (move_uploaded_file($_FILES['upload_file']['tmp_name'], UPLOAD_PATH . '/' . $_FILES['upload_file']['name'])) {
$img_path = UPLOAD_PATH . '/' . $file_name;
$is_upload = true;
}
} 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！';
}
}
win下的小技巧：Win下xx.jpg[空格] 或xx.jpg.这两类文件都是不允许存在的，若这样命名，windows会默认除去空格或点
此处会删除末尾的点，但是没有去掉末尾的空格，因此上传一个.php空格文件即可绕过。
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",".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']);
$file_ext = strrchr($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, $deny_ext)) {
if (move_uploaded_file($_FILES['upload_file']['tmp_name'], UPLOAD_PATH . '/' . $_FILES['upload_file']['name'])) {
$img_path = UPLOAD_PATH . '/' . $file_name;
$is_upload = true;
}
} 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！';
}
}
此处会删除末尾的空格，但是没有去掉末尾的点，因此上传一个.php.文件即可绕过。
Pass-08
$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",".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
$file_ext = trim($file_ext); //首尾去空
if (!in_array($file_ext, $deny_ext)) {
if (move_uploaded_file($_FILES['upload_file']['tmp_name'], UPLOAD_PATH . '/' . $_FILES['upload_file']['name'])) {
$img_path = UPLOAD_PATH . '/' . $file_name;
$is_upload = true;
}
} else {
$msg = '此文件不允许上传';
}
} else {
$msg = UPLOAD_PATH . '文件夹不存在,请手工创建！';
}
}
发现缺少::$DATA
查阅资料发现，这是利用windows操作系统的一个特性：
NTFS文件系统包括对备用数据流的支持。这不是众所周知的功能，主要包括提供与Macintosh文件系统中的文件的兼容性。备用数据流允许文件包含多个数据流。每个文件至少有一个数据流。在Windows中，此默认数据流称为：$ DATA。
上传.php::$DATA绕过。(仅限windows)
Pass-09
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",".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, $deny_ext)) {
if (move_uploaded_file($_FILES['upload_file']['tmp_name'], UPLOAD_PATH . '/' . $_FILES['upload_file']['name'])) {
$img_path = UPLOAD_PATH . '/' . $file_name;
$is_upload = true;
}
} 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！';
}
}
通过阅读源码，我们可以发现,用户上传的文件名，我们可控。且会删除文件名末尾的点和空格
结合上面几关的解题经验，我们可以发现可以通过创建文件.php.空格.来进行绕过
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","jsp","jspa","jspx","jsw","jsv","jspf","jtml","asp","aspx","asa","asax","ascx","ashx","asmx","cer","swf","htaccess");
$file_name = trim($_FILES['upload_file']['name']);
$file_name = str_ireplace($deny_ext,"", $file_name);
if (move_uploaded_file($_FILES['upload_file']['tmp_name'], UPLOAD_PATH . '/' . $file_name)) {
$img_path = UPLOAD_PATH . '/' .$file_name;
$is_upload = true;
}
} else {
$msg = UPLOAD_PATH . '文件夹不存在,请手工创建！';
}
}
通过查看源码发现
$file_name = str_ireplace($deny_ext,"", $file_name);
将黑名单的文件名替换成空，所以我们想到可以通过双写来进行绕过。
Pass-11
$is_upload = false;
$msg = null;
if(isset($_POST['submit'])){
$ext_arr = array('jpg','png','gif');
$file_ext = substr($_FILES['upload_file']['name'],strrpos($_FILES['upload_file']['name'],".")+1);
if(in_array($file_ext,$ext_arr)){
$temp_file = $_FILES['upload_file']['tmp_name'];
$img_path = $_GET['save_path']."/".rand(10, 99).date("YmdHis").".".$file_ext;
if(move_uploaded_file($temp_file,$img_path)){
$is_upload = true;
}
else{
$msg = '上传失败！';
}
}
else{
$msg = "只允许上传.jpg|.png|.gif类型文件！";
}
}
影响版本：5.4.x<= 5.4.39, 5.5.x<= 5.5.23, 5.6.x <= 5.6.7
exp：move_uploaded_file($_FILES['name']['tmp_name'],"/file.php\x00.jpg");
源码中move_uploaded_file中的save_path可控，因此00截断即可。
Pass-12
方法同上，只是请求方式改为POST
Pass-13
提示
本pass检查图标内容开头2个字节！
我们可以伪造一下文件头的信息
常用文件头：
（1） .JPEG;.JPE;.JPG，”JPGGraphic File”
（2） .gif，”GIF 89A”
（3） .zip，”Zip Compressed”
（4） .doc;.xls;.xlt;.ppt;.apr，”MS Compound Document v1 or Lotus Approach APRfile”
Pass-14
本关可以通过制作图片马进行绕过
制作图片马的方法：
在Windows的cmd中执行命令：
copy 图片名/b+ 木马文件/a 合成的图片马名
Pass-15
同14关
Pass-16
主要是二次渲染绕过
jpg和png很麻烦，gif只需要找到渲染前后没有变化的位置,然后将php代码写进去,就可以了。
二次渲染的详解
Pass-17
$is_upload = false;
$msg = null;
if(isset($_POST['submit'])){
$ext_arr = array('jpg','png','gif');
$file_name = $_FILES['upload_file']['name'];
$temp_file = $_FILES['upload_file']['tmp_name'];
$file_ext = substr($file_name,strrpos($file_name,".")+1);
$upload_file = UPLOAD_PATH . '/' . $file_name;
if(move_uploaded_file($temp_file, $upload_file)){
if(in_array($file_ext,$ext_arr)){
$img_path = UPLOAD_PATH . '/'. rand(10, 99).date("YmdHis").".".$file_ext;
rename($upload_file, $img_path);
$is_upload = true;
}else{
$msg = "只允许上传.jpg|.png|.gif类型文件！";
unlink($upload_file);
}
}else{
$msg = '上传失败！';
}
}
可以看到文件先经过保存，然后判断后缀名是否在白名单中，如果不在则删除，此时可以利用条件竞争在保存文件后删除文件前来执行php文件。
一边用bp一直上传木马文件，一边用脚本一直访问该临时文件，就能成功执行命令。
Pass-18
原理同17一样，都是利用条件竞争
Pass-19
$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");
$file_name = $_POST['save_name'];
$file_ext = pathinfo($file_name,PATHINFO_EXTENSION);
if(!in_array($file_ext,$deny_ext)) {
$img_path = UPLOAD_PATH . '/' .$file_name;
if (move_uploaded_file($_FILES['upload_file']['tmp_name'], $img_path)) {
$is_upload = true;
}else{
$msg = '上传失败！';
}
}else{
$msg = '禁止保存为该类型文件！';
}
} else {
$msg = UPLOAD_PATH . '文件夹不存在,请手工创建！';
}
}
这里需要注意的是move_uploaded_file会忽略掉文件末尾的/.这里是用户可控的。所以我们可以伪造这样的上传
总结
感觉这个图总结的特别详细。
自己还是很菜，还要继续努力呀！