全网最全upload-labs通关攻略(建议收藏)
Upload-labs是一个帮你总结所有上传漏洞类型的靶场,学习上传漏洞原理,复现上传漏洞必备靶场环境,玩起来吧!项目地址:https://github.com/c0ny1/upload-labs
环境要求
若要自己亲自搭建环境,请按照以下配置环境,方可正常运行每个Pass。
配置项 | 配置 | 描述 |
---|---|---|
操作系统 | Window or Linux | 推荐使用Windows,除了Pass-19必须在linux下,其余Pass都可以在Windows上运行 |
PHP版本 | 推荐5.2.17 | 其他版本可能会导致部分Pass无法突破 |
PHP组件 | php_gd2,php_exif | 部分Pass依赖这两个组件 |
中间件 | 设置Apache | 以moudel方式连接 |
第一关
思路发现
- 随意上传php木马,发现前端报错,响应速度超快,且数据包未达到服务器,猜测前端js验证
源码解读
function checkFile() {
var file = document.getElementsByName('upload_file')[0].value;
if (file == null || file == "") {
alert("请选择要上传的文件!");
return false;
}
//定义允许上传的文件类型
var allow_ext = ".jpg|.png|.gif";
//提取上传文件的类型
var ext_name = file.substring(file.lastIndexOf("."));
//判断上传文件类型是否允许上传
if (allow_ext.indexOf(ext_name + "|") == -1) {
var errMsg = "该文件不允许上传,请上传" + allow_ext + "类型的文件,当前文件类型为:" + ext_name;
alert(errMsg);
return false;
}
}
- 逻辑大致是识别上传文件的后缀名 并查看是否是jpg、png、gif中的一个,否则不允许上传
bypass
1.修改前端不使用该checkfile函数
- 直接可上传php文件成功
第二关
思路发现
- 上传php显示文件类型不正确
- 抓包查看文件类型字段,猜测会判断Content-Type字段
源码解读
$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')) {
$temp_file = $_FILES['upload_file']['tmp_name'];
$img_path = UPLOAD_PATH . '/' . $_FILES['upload_file']['name']
if (move_uploaded_file($temp_file, $img_path)) {
$is_upload = true;
} else {
$msg = '上传出错!';
}
} 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!';
}
}
- 逻辑大致是识别上传文件的类型 并查看是否是image/jpge、image/png、image/gif中的一个,否则不允许上传
- $_FILES全局变量
$_FILES'myFile' | 上传文件的原名称 |
---|---|
$_FILES'myFile' | 文件的 MIME 类型 |
$_FILES'myFile' | 已上传文件的大小,单位为字节 |
$_FILES'myFile' | 文件被上传后在服务端储存的临时文件名,一般是系统默认。可以在php.ini的upload_tmp_dir 指定 |
$_FILES'myFile' | 和该文件上传相关的错误代码 |
bypass
直接抓包改Content-Type为image/png,上传成功
第三关
思路发现
- 直接上传php脚本显示提示:不允许上传.asp,.aspx,.php,.jsp后缀文件!
- 猜测设置了后缀名黑名单
源码解读
$is_upload = false;
$msg = null;
if (isset($_POST['submit'])) {
if (file_exists(UPLOAD_PATH)) {
$deny_ext = array('.asp','.aspx','.php','.jsp');
$file_name = trim($_FILES['upload_file']['name']);
$file_name = deldot($file_name);//删除文件名末尾的点
$file_ext = strrchr($file_name, '.'); // 截取'.'后的后缀名
$file_ext = strtolower($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;// 随机命名
if (move_uploaded_file($temp_file,$img_path)) {
$is_upload = true;
} else {
$msg = '上传出错!';
}
} else {
$msg = '不允许上传.asp,.aspx,.php,.jsp后缀文件!';
}
} else {
$msg = UPLOAD_PATH . '文件夹不存在,请手工创建!';
}
}
- 逻辑大致是识别上传文件的类型 并查看是否是'.asp','.aspx','.php','.jsp'中的一个,否则不允许上传
bypass
- 尝试使用和php一样解析效果的后缀名,如php3、php4、php5、phtml等后缀名
- 上传成功,并成功解析
第四关
思路发现
- 直接上传php脚本显示提示:此文件不允许上传!
- 需抓包验证检验的参数
源码解读
$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",".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); //收尾去空
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 = '此文件不允许上传!';
}
} else {
$msg = UPLOAD_PATH . '文件夹不存在,请手工创建!';
}
}
- 逻辑大致大致和上一关类似,只是增加了黑名单量,识别上传文件的类型 并查看是否是黑名单量中的一个,否则不允许上传,可见大小写都包括了,常见的一些后缀也包括了,通过查看资料发现.htaccess后缀文件并未在这个黑名单中,可以进行利用。
bypass
- 上传一个.htaccess文件
- 内容如下,意思为所有文件都用php来解析
AddType application/x-httpd-php .png
或者
<FilesMatch "文件名">
SetHandler application/x-httpd-php
</FilesMatch>
- 上传一个图片马hacker.png
- 直接访问该图片地址,均成功!
第五关
思路发现
- 和上一关类似
源码解读
$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!';
}
}
- 逻辑大致大致和上一关类似,只是增加了.htaccess黑名单量,识别上传文件的类型 并查看是否是黑名单量中的一个,否则不允许上传,细看大小写过滤并不全,可以混合大小写进行利用。
bypass
- 上传shell.PhP上传成功
第六关
源码解读
$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!';
}
}
- PHP _FILES 是一个预定义的数组,用来获取通过 POST 方法上传文件的相关信息。如果为单个文件上传,那么 FILES 为二维数组;如果为多个文件上传,那么
Array
(
[userfile] => Array
(
[name] => Screen Shot 2016-05-12 at 18.13.24.png
[type] => image/png
[tmp_name] => /private/var/tmp/phplVHp3W
[error] => 0
[size] => 344925
)
)
- 是后缀名黑名单,少了这段代码file_ext = trim(file_ext); //首尾去空
bypass
可以进行空格绕过,直接抓包修改文件名,再文件名末尾添加空格,成功上传
- 直接可上传php文件成功
第七关
源码解读
$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!';
}
}
- 没有对后缀名进行去”.”处理,strrchr(file_name, '.')只是截取.后面的后缀名。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。少了代码file_name = deldot(
bypass
查看源码还是黑名单没有对后缀名进行去.操作利用Windows特性会自动去掉后缀名中最后的.可在后缀名中加 . 绕过
第八关
源码解读
$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!';
}
}
- 逻辑大致是识别上传文件的类型 并查看是否是'.asp','.aspx','.php','.jsp'中的一个,否则不允许上传,少了代码file_ext = str_ireplace('::DATA', '', file_ext);//去除字符串::DATA
bypass
- NTFS文件系统包括对备用数据流的支持,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)
第九关
源码解读
$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!';
}
}
- 查看源码,这里只过滤了一次,所以直接构造 .php. . 绕过
bypass
直接构造点加空格加点 .php. . 绕过
可通过https://localhost/upload-labs/upload/shell1.php访问mm
第十关
源码解读
$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!';
}
}
- file_name = str_ireplace(deny_ext,"",
bypass
1.双写绕过
第十一关
源码解读
$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!";
}
}
- strrpos() 函数查找字符串在另一字符串中最后一次出现的位置
- 是后缀名白名单,截取后缀名并随机命名拼接
bypass
$_GET['save_path'] 有传入参数可控,可以使用%00截断
第十二关
源码解读
$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{
$msg = "只允许上传.jpg|.png|.gif类型文件!";
}
}
- 与前一关类似,只是变成了POST提交
bypass
%00截断进行拼接
第十三关
源码解读
function getReailFileType($filename){
$file = fopen($filename, "rb");
$bin = fread($file, 2); //只读2字节 读取文件头
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{
$msg = "上传失败";
}
}
}
- 会读取文件头和文件类型,已提示传入图片mm
bypass
制作图片mm上传
结合文件包含进行解析
第十四关
源码解读
function isImage($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{
$msg = "上传失败";
}
}
}
这里用getimagesize获取文件类型
bypass
还是直接就可以利用图片马就可进行绕过
第十五关
源码解读
function isImage($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";
}
}
}
这里用到php_exif模块来判断文件类型
bypass
还是直接就可以利用图片马就可进行绕过
第十六关
源码解读
$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!";
}
}
- 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,最后再做了一次二次渲染
bypass
第十七关
源码解读
$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, $upload_file)){
// 先移动图片,有条件竞争的前提条件
if(in_array($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!';
}
}
- 这里先将文件上传到服务器,然后通过rename修改名称,再通过unlink删除文件,因此可以通过条件竞争的方式在unlink之前,访问webshell
bypass
首先在burp中不断发送上传webshell的数据包,然后不断在浏览器中访问,发现通过竞争可以访问到。
第十八关
源码解读
/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" );
}
......
......
......
};
- 需要上传一个图片mm
- 本关对文件后缀名做了白名单判断,然后会一步一步检查文件大小、文件是否存在等等
bypass
将文件上传后,对文件重新命名,同样存在条件竞争的漏洞。可以不断利用burp发送上传图片马的数据包,由于条件竞争,程序会出现来不及rename的问题,从而上传成功:
第十九关
源码解读
$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!';
}
}
- file_name = _POST['save_name'];中有变量可控发现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:
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