upload-labs闯关
作者:互联网
下载安装
源码地址:
https://github.com/c0ny1/upload-labs
安装:
直接放在phpstudy的www目录中
Pass-01 js检查
源码:
方法一:
直接禁用js
F12—设置——禁用js
方法二:
抓包修改文件类型,上传1.png修改为1.php
方法三:
通过修改前端代码添加.php文件进行上传
方法四:
右键-查看网站源代码-全部复制-创建一个记事本-把代码放进去-把记事本名后缀改为.html-打开-删除js代码
如果我们打开,是有上传文件的界面,但是不知道要上传给谁。这时我们返回到最开始,右键—检查—网络—然后上传一个正常的图片。这样我们就可以看到这个文件传给谁了。
打开我们自己的html文件,修改action,这个action是告诉他这个图片提交给谁,因为这个源代码中没有,我们就自己加一个。
最后用浏览器打开我们的html文件,上传php文件即可。
Pass-02 MIME类型 检测
源码:
通过抓包,将Content-Type修改为允许上传的类型(image/jpeg、image/png、image/gif)三选一。
Pass-03 黑名单绕过
通过查看源码,发现不允许上传.asp,.aspx,.php,.jsp后缀的文件,可以尝试上传后缀.phtml .phps .php5 .pht的文件
修改apache的httpd.conf中的如下配置代码
保存,重启phpstudy
上传php5文件,成功绕过
Pass-04 .htaccess绕过
查看源码
黑名单拒绝了几乎所有有问题的后缀名,除了.htaccess
首先上传.htaccess文件
<FilesMatch "4.png">
SetHandler application/x-httpd-php
</FilesMatch>
如果文件中有一个4.png的文件,他就会被解析为.php,把这个文件上传上去。
1.首先上传.htaccess文件
2、上传4.png文件
3、成功被解析为php文件
Pass-05 大小写绕过
源码:
$is_upload = false;
$msg = null;
if (isset($_POST['submit'])) {
if (file_exists($UPLOAD_ADDR)) {
$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_ADDR . '/' . $_FILES['upload_file']['name'])) {
$img_path = $UPLOAD_ADDR . '/' . $file_name;
$is_upload = true;
}
} else {
$msg = '此文件不允许上传';
}
} else {
$msg = $UPLOAD_ADDR . '文件夹不存在,请手工创建!';
}
}
通过查看源码,发现相比于pass-04,过滤了.htaccess,但将后缀转换为小写去掉了,因此可以使用大小绕过
直接上传5.PHP文件,即可绕过
Pass-06 空格绕过
源码
$is_upload = false;
$msg = null;
if (isset($_POST['submit'])) {
if (file_exists($UPLOAD_ADDR)) {
$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
if (!in_array($file_ext, $deny_ext)) {
if (move_uploaded_file($_FILES['upload_file']['tmp_name'], $UPLOAD_ADDR . '/' . $_FILES['upload_file']['name'])) {
$img_path = $UPLOAD_ADDR . '/' . $file_name;
$is_upload = true;
}
} else {
$msg = '此文件不允许上传';
}
} else {
$msg = $UPLOAD_ADDR . '文件夹不存在,请手工创建!';
}
}
相比于前两题,这题没有对后缀名进行去空,因此可以在后缀名加空格绕过
Pass-07 点绕过
源码:
$is_upload = false;
$msg = null;
if (isset($_POST['submit'])) {
if (file_exists($UPLOAD_ADDR)) {
$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_ADDR . '/' . $_FILES['upload_file']['name'])) {
$img_path = $UPLOAD_ADDR . '/' . $file_name;
$is_upload = true;
}
} else {
$msg = '此文件不允许上传';
}
} else {
$msg = $UPLOAD_ADDR . '文件夹不存在,请手工创建!';
}
}
通过查看源码发现没有对后缀名末尾的点进行处理,利用windows特性,会自动去掉后缀名中最后的”.”,可在后缀名中加”.”绕过:
Pass-08 ::$DATA绕过
源码:
$is_upload = false;
$msg = null;
if (isset($_POST['submit'])) {
if (file_exists($UPLOAD_ADDR)) {
$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_ADDR . '/' . $_FILES['upload_file']['name'])) {
$img_path = $UPLOAD_ADDR . '/' . $file_name;
$is_upload = true;
}
} else {
$msg = '此文件不允许上传';
}
} else {
$msg = $UPLOAD_ADDR . '文件夹不存在,请手工创建!';
}
}
通过查看源码发现没有去除字符串::$DATA
$file_ext = str_ireplace('::$DATA', '', $file_ext);//去除字符串::$DATA
php+windows的情况下: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::$DATA"之前的文件名。利用windows特性,可在后缀名中加” ::$DATA”绕过:
Pass-09 点+空格+点绕过
源码:
$is_upload = false;
$msg = null;
if (isset($_POST['submit'])) {
if (file_exists($UPLOAD_ADDR)) {
$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_ADDR . '/' . $_FILES['upload_file']['name'])) {
$img_path = $UPLOAD_ADDR . '/' . $file_name;
$is_upload = true;
}
} else {
$msg = '此文件不允许上传';
}
} else {
$msg = $UPLOAD_ADDR . '文件夹不存在,请手工创建!';
}
}
通过代码分析,它没有循环验证,也就是说这些收尾去空,删除末尾的点,去除字符串::$DATA,转换为小写这些东西只是验证了一次。所以我们的绕过思路就很简单,在数据包中把后缀名改为.php. .说一下他的验证过程,首先他发现有一个点,这时会把他去掉,又发现有一个空格,也会把它去掉,我们这时还有一个点,也就是.php. 由于他只是验证一次,所以不会在去掉我们的点,这时就可以上传成功,也可以解析成功。如下图:
Pass-10 双写绕过
源码:
$is_upload = false;
$msg = null;
if (isset($_POST['submit'])) {
if (file_exists($UPLOAD_ADDR)) {
$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_ADDR . '/' . $file_name)) {
$img_path = $UPLOAD_ADDR . '/' .$file_name;
$is_upload = true;
}
} else {
$msg = $UPLOAD_ADDR . '文件夹不存在,请手工创建!';
}
}
阅读源码可以发现,这里将把上传的文件名中所有包含黑名单字符的,全部替换为空,所以这里可以利用双写来绕过, xx.p[php]hp
Pass-11 00截断
源码:
$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{
$msg = "只允许上传.jpg|.png|.gif类型文件!";
}
}
白名单判断,但$img_path是直接拼接,因此可以利用%00截断绕过。
$img_path = $_GET['save_path']."/".rand(10, 99).date("YmdHis").".".$file_ext;
截断条件:php版本小于5.3.4,php的magic_quotes_gpc为OFF状态
Pass-12 00截断
源码:
$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 = $_POST['save_path']."/".rand(10, 99).date("YmdHis").".".$file_ext;
if(move_uploaded_file($temp_file,$img_path)){
$is_upload = true;
}
else{
$msg = "上传失败";
}
}
else{
$msg = "只允许上传.jpg|.png|.gif类型文件!";
}
}
与上一关差不多,只是save_path参数通过POST方式传递,还是利用00截断,因为POST不会像GET对%00进行自动解码,所以需要在二进制中进行修改。
上传成功
Pass-13 图片马绕过
源码:
function getReailFileType($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 = $UPLOAD_ADDR."/".rand(10, 99).date("YmdHis").".".$file_type;
if(move_uploaded_file($temp_file,$img_path)){
$is_upload = true;
}
else{
$msg = "上传失败";
}
}
}
查看源码发现,通过文件的前2个字节判断文件类型,因此可以通过上传图片马进行绕过
方法一:
使用命令制作图片马
使用命令 copy 13.jpg /b + 13.php /a webshell.jpg制作图片马
上传文件:
使用文件包含漏洞测试
##include.php
<?php
/*
本页面存在文件包含漏洞,用于测试图片马是否能正常运行!
*/
header("Content-Type:text/html;charset=utf-8");
$file = $_GET['file'];
if(isset($file)){
include $file;
}else{
show_source(__file__);
}
?>
方法二:
在php文件头部写入GIF89a,并修改文件后缀为图片形式
Pass-14 getimagesize()-图片马
源码:
function isImage($filename){
$types = '.jpeg|.png|.gif';
if(file_exists($filename)){
$info = getimagesize($filename);
$ext = image_type_to_extension($info[2]);
if(stripos($types,$ext)){
return $ext;
}else{
return false;
}
}else{
return false;
}
}
$is_upload = false;
$msg = null;
if(isset($_POST['submit'])){
$temp_file = $_FILES['upload_file']['tmp_name'];
$res = isImage($temp_file);
if(!$res){
$msg = "文件未知,上传失败!";
}else{
$img_path = $UPLOAD_ADDR."/".rand(10, 99).date("YmdHis").$res;
if(move_uploaded_file($temp_file,$img_path)){
$is_upload = true;
}
else{
$msg = "上传失败";
}
}
}
通过源码发现,通过getimagesize函数判断文件类型,但是这个函数也是检查文件头,同样可以通过图片马绕过,方法同pass-13
pass-15 exif_imagetype()-图片马
源码:
function isImage($filename){
//需要开启php_exif模块
$image_type = exif_imagetype($filename);
switch ($image_type) {
case IMAGETYPE_GIF:
return "gif";
break;
case IMAGETYPE_JPEG:
return "jpg";
break;
case IMAGETYPE_PNG:
return "png";
break;
default:
return false;
break;
}
}
$is_upload = false;
$msg = null;
if(isset($_POST['submit'])){
$temp_file = $_FILES['upload_file']['tmp_name'];
$res = isImage($temp_file);
if(!$res){
$msg = "文件未知,上传失败!";
}else{
$img_path = $UPLOAD_ADDR."/".rand(10, 99).date("YmdHis").".".$res;
if(move_uploaded_file($temp_file,$img_path)){
$is_upload = true;
}
else{
$msg = "上传失败";
}
}
}
exif_imagetype() 读取一个图像的第一个字节并检查其签名,所以仍然可以通过图片马绕过,方法同pass-13、pass-14
首先开启php_exif模块
Pass-16 二次渲染绕过
源码:
$is_upload = false;
$msg = null;
if (isset($_POST['submit'])){
// 获得上传文件的基本信息,文件名,类型,大小,临时文件路径
$filename = $_FILES['upload_file']['name'];
$filetype = $_FILES['upload_file']['type'];
$tmpname = $_FILES['upload_file']['tmp_name'];
$target_path=$UPLOAD_ADDR.basename($filename);
// 获得上传文件的扩展名
$fileext= substr(strrchr($filename,"."),1);
//判断文件后缀与类型,合法才进行上传操作
if(($fileext == "jpg") && ($filetype=="image/jpeg")){
if(move_uploaded_file($tmpname,$target_path))
{
//使用上传的图片生成新的图片
$im = imagecreatefromjpeg($target_path);
if($im == false){
$msg = "该文件不是jpg格式的图片!";
}else{
//给新图片指定文件名
srand(time());
$newfilename = strval(rand()).".jpg";
$newimagepath = $UPLOAD_ADDR.$newfilename;
imagejpeg($im,$newimagepath);
//显示二次渲染后的图片(使用用户上传图片生成的新图片)
$img_path = $UPLOAD_ADDR.$newfilename;
unlink($target_path);
$is_upload = true;
}
}
else
{
$msg = "上传失败!";
}
}else if(($fileext == "png") && ($filetype=="image/png")){
if(move_uploaded_file($tmpname,$target_path))
{
//使用上传的图片生成新的图片
$im = imagecreatefrompng($target_path);
if($im == false){
$msg = "该文件不是png格式的图片!";
}else{
//给新图片指定文件名
srand(time());
$newfilename = strval(rand()).".png";
$newimagepath = $UPLOAD_ADDR.$newfilename;
imagepng($im,$newimagepath);
//显示二次渲染后的图片(使用用户上传图片生成的新图片)
$img_path = $UPLOAD_ADDR.$newfilename;
unlink($target_path);
$is_upload = true;
}
}
else
{
$msg = "上传失败!";
}
}else if(($fileext == "gif") && ($filetype=="image/gif")){
if(move_uploaded_file($tmpname,$target_path))
{
//使用上传的图片生成新的图片
$im = imagecreatefromgif($target_path);
if($im == false){
$msg = "该文件不是gif格式的图片!";
}else{
//给新图片指定文件名
srand(time());
$newfilename = strval(rand()).".gif";
$newimagepath = $UPLOAD_ADDR.$newfilename;
imagegif($im,$newimagepath);
//显示二次渲染后的图片(使用用户上传图片生成的新图片)
$img_path = $UPLOAD_ADDR.$newfilename;
unlink($target_path);
$is_upload = true;
}
}
else
{
$msg = "上传失败!";
}
}else{
$msg = "只允许上传后缀为.jpg|.png|.gif的图片文件!";
}
}
imagecreatefromjpeg()函数
二次渲染是由Gif文件或 URL 创建一个新图象。成功则返回一图像标识符/图像资源,失败则返回false,导致图片马的数据丢失,上传图片马失败。
进行通关
按照原来的方法进行上传,我们可以发现还是可以上传的,但是配合包含漏洞却无法解析,这时我们把上传的图片复制下来用Notepad打开,发现我们原来写的php代码没有了,这就是二次渲染把我们里面的php代码删掉了。
我们把原图和他修改过的图片进行比较,看看哪个部分没有被修改。将php代码放到没有被更改的部分,配合包含漏洞,就可以了。
使用HxD Hex Editor进行比较
下载地址:https://mh-nexus.de/en/hxd
然后比较
具体实现需要自己编写Python程序,人工尝试基本是不可能构造出能绕过渲染函数的图片webshell的,知道怎么解就可以了。
Pass-17 条件竞争
源码:
$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_ADDR . '/' . $file_name;
if(move_uploaded_file($temp_file, $upload_file)){
if(in_array($file_ext,$ext_arr)){
$img_path = $UPLOAD_ADDR . '/'. rand(10, 99).date("YmdHis").".".$file_ext;
rename($upload_file, $img_path);
unlink($upload_file);
$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!';
}
}
通过源码,发现先将图片上传上去,才开始进行判断后缀名、二次渲染,如果不是指定类型,那么删除该文件,在文件上传成功后和删除文件之前有一个时间差,如果在这个时间内访问上传的PHP文件,从而执行其中的代码
可以利用burp的intruder模块不断上传,然后我们不断的访问刷新该地址即可
修改线程
Pass-18 条件竞争
源码:
//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_ADDR);
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" );
}
......
......
......
};
方法一:上传图片马
方法二:
上面源码的代码逻辑:
1、首先接收上传的文件
2、然后判断上传的文件的文件后缀是否在白名单中
3、在白名单中,则将文件重命名
4、不在白名单则删除文件
通过不断发送请求包,直到访问shell.php成功为止
Pass-19 常见中间件解析漏洞
源码:
$is_upload = false;
$msg = null;
if (isset($_POST['submit'])) {
if (file_exists($UPLOAD_ADDR)) {
$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 = $UPLOAD_ADDR . '/' .$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_ADDR . '文件夹不存在,请手工创建!';
}
}
方法一:
move_uploaded_file()有这么一个特性,会忽略掉文件末尾的.
保存文件名可以自定义,不能直接保存为php,在php后面加一个. 成功绕过
方法二:上传19.jpg,在save_name处用00截断
move_uploaded_file()函数中的img_path是由post参数save_name控制的,可以在save_name利用%00截断(注意php版本低于5.3)。
完毕!
参考
https://www.cnblogs.com/chu-jian/p/15515770.html
标签:name,上传,upload,labs,ext,file,msg,闯关 来源: https://blog.csdn.net/weixin_42728957/article/details/121761146