最近在练习文件上传，所以记录一下自己练习的过程，既能帮助自己以后复习，同时也能帮到初学者。
主要用到的工具是Burpsuite。首先我们应该明白上传文件的目的是什么，通过上传文件将web后门上传并被成功解析。
Pass-01
首先查看源码
通过源码可以看到，第一关是在本地前段进行验证，使用的是前端JS脚本，所以呢，你让它不起作用不就完了，前端我们是可以修改的，在前端JS函数中加上.php文件，然后上传PHP文件。（具体怎么修改，直接查看源代码，然后修改，然后保存本地，再然后点击访问，然后上传即可）
Pass-02
源码：
这个其实也很简单，我们发现它只判断content-type，那所以只要burpsuite抓包修改content-type的类型就可以成功绕过，然后上传。
上传成功如图：
Pass-03
步骤一样，第一步先查看源码
通过源代码分析，我们能够看出来是黑名单过滤，这里有很多绕过方式，抓包修改后缀为php5、php3、phtml、pht等可解析的文件后缀即可
Pass-04
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","php1",".html",".htm",".phtml",".pht",".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)) {
$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！';
}
}
还是黑名单过滤，几乎过滤了所有后缀名，但是没有过滤.htaccess，所有先上传一个后缀名为.htaccess文件，里面写上SetHandler application/x-httpd-php，之后所有的文件都会以PHP文件进行解析，那就正常上传图片，然后访问即可
此处用到知识点：
.htaccess文件 -服务
通过.htaccess文件修改解析规则
条件：必须为apache搭建平台
Pass-05
这一关和上一关几乎一模一样，但是没有进行大小写过滤，所以，大小写修改后缀名，然后成功上传。
上传结果如图：
Pass-06
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",".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 = $_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！';
}
}
仍然是过滤了很多后缀名，这个时候我们可以在后面加后缀名后面加空格进行绕过
结果如图所示：
成功上传！
Pass-07
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",".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']);
$file_ext = strrchr($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！';
}
}
第7关我们发现多了一个函数，就是首位去空，发现加空格以不再有效。那就没有别的了吗？
当然不是了，出了空格还有很多可以加，它虽然过滤了空格，但是没有过滤“.”！所以，我们可以在后缀名后面加“.”即可绕过上传，正所谓，条条大路通罗马，这里我们也可以看出来，黑名单的弊端！
成功
Pass-08
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",".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
$file_ext = trim($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！';
}
}
这里我们发现，大小写不行，加点不行，加空格也不行，但是没有对::\(DATA进行过滤,所以在后缀名中加::\)DATA进行绕过
知识点：
文件名+::\(DATA - 服务 必须是windows, 必须是php, php在window的时候如果文件名+"::\)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
他的目的就是不检查后缀名....
成功
Pass-09
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",".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 {
$msg = UPLOAD_PATH . '文件夹不存在,请手工创建！';
}
}
这里，在后缀后加上 点+空格+点 即可成功绕过，
pass-10
这里的步骤和之前的一样，重复的我就不再写了，浪费时间，还是先看源码，这是第一步，通过源码去分析它是黑名单过滤还是白名单，然后看它漏掉了哪项。
第10关采用双写绕过，后缀名为 .phphpp 即可成功上传，结果一样，我就不再一一截图了。
Pass-11
查看源码，我们发现11关是白名单判断，因此可以采用%00截断绕过
但是有环境限制： php版本要小于5.3.4，5.3.4及以上
magic_quotes_gpc需要为OFF状态
如果你在做实验时发现一直上传错误，请看你是否满足我上面说的两个环境限制，如果不满足就会上传错误，如果已经设置好，则可以正常上传，得到正确结果。
Pass-12
这一关和11关一样，只是这个是POST提交，上面那个是GET提交，用的方法是一样的！
这里就不再过多阐述
Pass-13
源码：
function getReailFileType($filename){
$file = fopen($filename, "rb");
$bin = fread($file, 2); //只读2字节
fclose($file);
$strInfo = @unpack("C2chars", $bin);
$typeCode = intval($strInfo['chars1'].$strInfo['chars2']);
$fileType = '';
switch($typeCode){
case 255216:
$fileType = 'jpg';
break;
case 13780:
$fileType = 'png';
break;
case 7173:
$fileType = 'gif';
break;
default:
$fileType = 'unknown';
}
return $fileType;
}
$is_upload = false;
$msg = null;
if(isset($_POST['submit'])){
$temp_file = $_FILES['upload_file']['tmp_name'];
$file_type = getReailFileType($temp_file);
if($file_type == 'unknown'){
$msg = "文件未知，上传失败！";
}else{
$img_path = UPLOAD_PATH."/".rand(10, 99).date("YmdHis").".".$file_type;
if(move_uploaded_file($temp_file,$img_path)){
$is_upload = true;
} else {
$msg = "上传出错！";
}
}
}
13关往后与之前不一样，13关之后的是上传图片马。
这里我们看到，它只判断前两个字节，所以自己搞一个图片，然后编辑，将一句话木马写进去，然后上传即可，访问即可得到。
图片上面是乱码，但下面就是被php解析的函数。
Pass-14
跟13关一样。
getimagesize判断图片内置函数可以参考官方文档http://php.net/manual/zh/function.getimagesize.php
Pass-15
这关需要开启php_exif模块，通过php_exif来判断函数类型，具体可以看官方文档http://php.net/manual/zh/function.exif-imagetype.php，接下来还是上传图片马
Pass-16
源码我就不贴了，占地，自己在自己的靶场可以看到。
本关综合判断了后缀名、content-type，以及利用imagecreatefromgif判断是否为gif图片，最后对图片再做了一次二次渲染重新创建，所以在上传图片马的时候将上传后的图片马下载下来进行查看，看看它经过而渲染后的图片中的那些数据没有改变，可以通过16进制编辑器查看，然后我们在这些没有变的地方插入一句话，这样就可以成功上传了。之后的操作与之前的关卡一样
Pass-17
本关考察的是条件竞争
通过白名单检测后缀名，符合就rename改名，不符合就unlink删除文件
可以用burp来发包不断访问，先写一个php写入文件的1.php然后在不断访问这文件就可以看到我们上传的东西了，而且在访问这文件就可以生成另外一个shell了（通过马生成的）
Pass-18
//index.php
$is_upload = false;
$msg = null;
if (isset($_POST['submit']))
{
require_once("./myupload.php");
$imgFileName =time();
$u = new MyUpload($_FILES['upload_file']['name'], $_FILES['upload_file']['tmp_name'], $_FILES['upload_file']['size'],$imgFileName);
$status_code = $u->upload(UPLOAD_PATH);
switch ($status_code) {
case 1:
$is_upload = true;
$img_path = $u->cls_upload_dir . $u->cls_file_rename_to;
break;
case 2:
$msg = '文件已经被上传，但没有重命名。';
break;
case -1:
$msg = '这个文件不能上传到服务器的临时文件存储目录。';
break;
case -2:
$msg = '上传失败，上传目录不可写。';
break;
case -3:
$msg = '上传失败，无法上传该类型文件。';
break;
case -4:
$msg = '上传失败，上传的文件过大。';
break;
case -5:
$msg = '上传失败，服务器已经存在相同名称文件。';
break;
case -6:
$msg = '文件无法上传，文件不能复制到目标目录。';
break;
default:
$msg = '未知错误！';
break;
}
}
//myupload.php
class MyUpload{
......
......
......
var $cls_arr_ext_accepted = array(
".doc", ".xls", ".txt", ".pdf", ".gif", ".jpg", ".zip", ".rar", ".7z",".ppt",
".html", ".xml", ".tiff", ".jpeg", ".png" );
......
......
......
/** upload()
**
** Method to upload the file.
** This is the only method to call outside the class.
** @para String name of directory we upload to
** @returns void
**/
function upload( $dir ){
$ret = $this->isUploadedFile();
if( $ret != 1 ){
return $this->resultUpload( $ret );
}
$ret = $this->setDir( $dir );
if( $ret != 1 ){
return $this->resultUpload( $ret );
}
$ret = $this->checkExtension();
if( $ret != 1 ){
return $this->resultUpload( $ret );
}
$ret = $this->checkSize();
if( $ret != 1 ){
return $this->resultUpload( $ret );
}
// if flag to check if the file exists is set to 1
if( $this->cls_file_exists == 1 ){
$ret = $this->checkFileExists();
if( $ret != 1 ){
return $this->resultUpload( $ret );
}
}
// if we are here, we are ready to move the file to destination
$ret = $this->move();
if( $ret != 1 ){
return $this->resultUpload( $ret );
}
// check if we need to rename the file
if( $this->cls_rename_file == 1 ){
$ret = $this->renameFile();
if( $ret != 1 ){
return $this->resultUpload( $ret );
}
}
// if we are here, everything worked as planned :)
return $this->resultUpload( "SUCCESS" );
}
......
......
......
};
和上一关几乎一模一样
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)) {
$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 = '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！';
}
}
本关考察CVE-2015-2348 move_uploaded_file() 00截断，上传webshell，同时自定义保存名称，直接保存为php是不行的,查看源码发现move_uploaded_file()函数中的img_path是由post参数save_name控制的，因此可以在save_name利用00截断绕过
Pass-20
$is_upload = false;
$msg = null;
if(!empty($_FILES['upload_file'])){
//检查MIME
$allow_type = array('image/jpeg','image/png','image/gif');
if(!in_array($_FILES['upload_file']['type'],$allow_type)){
$msg = "禁止上传该类型文件!";
}else{
//检查文件名
$file = empty($_POST['save_name']) ? $_FILES['upload_file']['name'] : $_POST['save_name'];
if (!is_array($file)) {
$file = explode('.', strtolower($file));
}
$ext = end($file);
$allow_suffix = array('jpg','png','gif');
if (!in_array($ext, $allow_suffix)) {
$msg = "禁止上传该后缀文件!";
}else{
$file_name = reset($file) . '.' . $file[count($file) - 1];
$temp_file = $_FILES['upload_file']['tmp_name'];
$img_path = UPLOAD_PATH . '/' .$file_name;
if (move_uploaded_file($temp_file, $img_path)) {
$msg = "文件上传成功！";
$is_upload = true;
} else {
$msg = "文件上传失败！";
}
}
}
}else{
$msg = "请选择要上传的文件！";
}
通过查看源码可以发现：
\(file_name经过reset(\)file) . '.' . \(file[count(\)file) - 1];处理。
如果上传的是数组的话，会跳过\(file = explode('.', strtolower(\)file));。
并且后缀有白名单过滤：
\(ext = end(\)file);
$allow_suffix = array('jpg','png','gif');
而最终的文件名后缀取的是\(file[count(\)file) - 1]，因此我们可以让$file为数组。
\(file[0]为smi1e.php/，也就是reset(\)file)，然后再令$file[2]为白名单中的jpg。
此时end(\(file)等于jpg，\)file[count($file) - 1]为空。
而 \(file_name = reset(\)file) . '.' . \(file[count(\)file) - 1];，也就是smi1e.php/.，最终move_uploaded_file会忽略掉/.，最终上传smi1e.php。
总结：
以上就是自己的一些笔记和经验，但是，试想一下，如果没有源代码，你又能通过几关呢？