思维导图
文件上传常见验证
后缀名，类型，文件头等
黑名单：明确不允许上传的格式后缀
如：$deny_ext = array(’.asp’,’.aspx’,’.php’,’.jsp’);
不允许上传后缀为asp, aspx ，php ，jsp 的文件
白名单：明确只允许上传的格式后缀
如：$ext_arr = array(‘jpg’,‘png’,‘gif’);
只允许上传jpg png gif 文件
文件类型：MIME 信息
MIME(Multipurpose Internet Mail Extensions)多用途互联网邮件扩展类型。是设定某种扩展名的文件用一种应用程序来打开的方式类型，当该扩展名文件被访问的时候，浏览器会自动使用指定应用程序来打开。多用于指定一些客户端自定义的文件名，以及一些媒体文件打开方式。
通用结构
type/subtype
MIME的组成结构非常简单；由类型与子类型两个字符串中间用'/'分隔而组成。不允许空格存在。type 表示可以被分多个子类的独立类别。subtype 表示细分后的每个类型。
MIME类型对大小写不敏感，但是传统写法都是小写
常见的MIME类型(通用型)：
PNG图像 .png image/png
GIF图形 .gif image/gif
JPEG图形 .jpeg,.jpg image/jpeg
任意的二进制数据 application/octet-stream
GZIP文件 .gz application/x-gzip
TAR文件 .tar application/x-tar
RTF文本 .rtf application/rtf
PDF文档 .pdf application/pdf
Word文件 .word application/msword
普通文本 .txt text/plain
html文档 .html text/html
xml文档 .xml text/xml
XHTML文档 .xhtml application/xhtml+xml
au声音文件 .au audio/basic
MIDI音乐文件 mid,.midi audio/midi,audio/x-midi
RealAudio音乐文件 .ra, .ram audio/x-pn-realaudio
MPEG文件 .mpg,.mpeg video/mpeg
AVI文件 .avi video/x-msvideo
Content-Type称之为MIME信息
文件头：内容头信息
百度百科文件头
各类文件头信息
常见的文件头信息对照表
gif
png
upload-labs-master 关卡分析
pass-1(前端验证）
原理：触发上传后会返回到checkFile（）函数进行图片不合法检测，checkFile()函数在js代码中，即客户端使用js对不合法图片进行检查。
绕过方式：
1-直接禁用浏览器js功能，然后上传shell脚本即可。
2-上传正常的文件后缀名，上传，然后抓包，改包，改为需要的后缀名。
上传成功
复制图像链接
http://127.0.0.1/upload-labs-master/upload/pass1.php
pass-2(白名单 MIME）
上传pass2.php，抓包，
把content-Type：application/octet-stream
改为白名单允许的类型即可
image/jpeg image/png image/gif
放包，上传成功
复制图像链接
http://127.0.0.1/upload-labs-master/upload/pass2.php
pass-3(黑名单 特殊解析后缀）
<?php
include '../config.php';
include '../common.php';
include '../head.php';
include '../menu.php';
$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']);//移除文件两端的空白符
$file_name = deldot($file_name);//删除文件名末尾的点
$file_ext = strrchr($file_name, '.');//返回从点往后的字符串 .xxxx yei
$file_ext = strtolower($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 = '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！';
}
}
?>相关函数知识
PHP trim() 函数
trim() 函数移除字符串两侧的空白字符或其他预定义字符。
trim(string,charlist)
string | 必需。规定要检查的字符串。 |
charlist | 可选。规定从字符串中删除哪些字符。如果被省略，则移除以下所有字符："\0" - NULL “\t” - 制表符 “\n” - 换行 “\x0B” - 垂直制表符 “\r” - 回车 " " - 空格 |
相关函数
ltrim() - 移除字符串左侧的空白字符或其他预定义字符
rtrim() - 移除字符串右侧的空白字符或其他预定义字符
PHP strrchr() 函数
strrchr() 函数查找字符串在另一个字符串中最后一次出现的位置，并返回从该位置到字符串结尾的所有字符
PHP str_ireplace() 函数
str_ireplace() 函数替换字符串中的一些字符（不区分大小写）
str_ireplace(find,replace,string,count)
find | 必需。规定要查找的值。 |
replace | 必需。规定替换 find 中的值的值。 |
string | 必需。规定被搜索的字符串。 |
count | 可选。一个变量，对替换数进行计数 |
str_ireplace(“WORLD”,“Shanghai”,“Hello world!”);
结果为：Hello Shanghai
不允许上传后缀为asp aspx php jsp 的文件。
可以利用 appache的特性
php php3 php5 phtml 都会当做php解析执行
上传pass3.php3
复制图片链接
http://127.0.0.1/upload-labs-master/upload/202203051325018349.php3
文件名变了，是因为有重命名
访问
apache 后缀名解析“漏洞”
pass-4(.htaccess解析）
仅存在于Apache中
.htaccess文件(或者"分布式配置文件"）,全称是Hypertext Access(超文本入口)。提供了针对目录改变配置的方法，即在一个特定的文档目录中放置一个包含一个或多个指令的文件， 以作用于此目录及其所有子目录。作为用户，所能使用的命令受到限制
概述来说，htaccess文件是Apache服务器中的一个配置文件，它负责相关目录下的网页配置。通过htaccess文件，可以帮我们实现：
网页301重定向、
自定义404错误页面、
改变文件扩展名、
允许/阻止特定的用户或者目录的访问、
禁止目录列表、
配置默认文档等功能。
需要的一些配置
1.要打开mod_rewrite模块
phpstudy软件界面——>其他选项菜单——PHP扩展及设置——Apache扩展——rewrite_module模块
2.AllowOverride All。
其他选项菜单——打开配置文件——httpd.conf 文件
搜索查找AllowOverride None，然后把AllowOverride None修改为 AllowOverride All，完成后保存
创建.htaccess文件
<FilesMatch "pass4">
Sethandler application/x-httpd-php
</FilesMatch >服务器会把文件名包含pass4的文件 当做php解析执行
pass4.jpg 内容
pass4.jpg
pass456.jpg
pass-5(.user.ini配置文件解析控制）
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",".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 {
$msg = UPLOAD_PATH . '文件夹不存在,请手工创建！';
}
}把所有可以解析的后缀名都给写死了，包括大小写转换，空格，还有点号，::$DATA
正常的php类文件上传不了了，并且拒绝上传 .htaccess 文件。
.user.ini。它比.htaccess 用的更广，不管服务器是 nginx/apache/IIS，当使用 CGI／
FastCGI 来解析 php 时，php 会优先搜索目录下所有的.ini 文件，并应用其中的配置。
类似于 apache 的.htaccess，但语法与.htacces 不同，语法跟 php.ini 一致。
[外链图片转存失败,源站可能有防盗链机制,建议将图片保存下来直接上传(img-OIWsFwzT-1646471990992)(QQ截图20220305150225.png)]
创建.user.ini 文件
auto_prepend_file=pass5.jpg把pass5.jpg当做php解析
pass5.jpg实际内容
<?php
echo 'good luck';
phpinfo();
?>先上传.user.ini 文件
再上传pass5.jpg
.user.ini 文件作用：所有的 php 文件都自动包含 pass5.jpg 文件。.user.ini 相当于一个用
户自定义的 php.ini。
其他：使用大小写绕过.htaccess . . 点空点进行绕过
pass-6(大小写绕过）
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",".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, '.');
$file_ext = str_ireplace('::$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'];
$img_path = UPLOAD_PATH.'/'.date("YmdHis").rand(1000,9999).$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！';
}
}对于文件名后缀的校验时，没有进行通用的大小转换后的校验-
strtolower()
大小写绕过原理：
Windows 系统下，对于文件名中的大小写不敏感。例如：test.php 和 TeSt.PHP 是一
样的。
Linux 系统下，对于文件名中的大小写敏感。例如：test.php 和 TesT.php 就是不一样
的。
绕过方法：文件后缀为.PHP即可
http://127.0.0.1/upload-labs-master/upload/202203051559117765.PHP
Pass-07(空格绕过）
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",".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！';
}
}对上传的文件名未做去空格的操作-> trim()
Windows 系统下，对于文件名中空格会被作为空处理，程序中的检测代码却不能自动删除空格。从而绕过黑名单。
绕过方法：burp 抓包，修改对应的文件名 添加空格。即可
http://127.0.0.1/upload-labs-master/upload/202203051604535072.php
Pass-08 (点号绕过）
$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']);
$file_ext = strrchr($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 {
$msg = UPLOAD_PATH . '文件夹不存在,请手工创建！';
}
}代码未对对上传的文件后缀名未做去点 . 的操作 -> strrchr($file_name, ‘.’)
利用 Windows 系统下，文件后缀名最后一个点会被自动去除。
绕过方法：文件后缀名为 .php.
http://127.0.0.1/upload-labs-master/upload/pass8.php.
Pass-09(::$DATA 绕过）
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",".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
$file_ext = trim($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 {
$msg = UPLOAD_PATH . '文件夹不存在,请手工创建！';
}
}未对上传的文件后缀名为做去 ::DATA"会把::
DATA之前的文件名，他的目的就是不检查后缀名**
例如:"phpinfo.php::$DATA"
Windows会自动去掉末尾的::$DATA变成"phpinfo.php
其中内容和所上传文件内容相同，并被解析。
绕过方法：上传带有一句话木马的文件，其文件名为pass9.php::$DATA
http://127.0.0.1/upload-labs-master/upload/202203051608257361.php::$data
http://127.0.0.1/upload-labs-master/upload/202203051608257361.php
pass-10(拼接绕过)
点空点绕过
pass10.php. .
$file_name = deldot($file_name);//删除文件名末尾的点 pass10.php.空格
$file_ext = strrchr($file_name, '.'); //.php.空格
$file_ext = strtolower($file_ext); //转换为小写 .php.空格
$file_ext = str_ireplace('::$DATA', '', $file_ext);//去除字符串::$DATA .php.空格
$file_ext = trim($file_ext); //首尾去空 .php.http://127.0.0.1/upload-labs-master/upload/pass10.php.
pass11(双写绕过)
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","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！';
}
}利用 str_ireplace()将文件名中符合黑名单的字符串替换成空，只过滤了一次，存在漏洞
绕过方式：利用双写黑名单字符，对字符串的一次过滤后拼接出 php,文件 名 .pphphp
http://127.0.0.1/upload-labs-master/upload/pass11.php
pass12(白名单 GET 型 0x00 截断)
使用白名单限制上传文件类型，但上传文件的存放路径可控，存在漏洞
产生条件：
需要 php 的版本号低于 5.3.29，且 magic_quotes_gpc 为关闭状态
（打开php的配置文件php-ini，将magic_quotes_gpc设置为Off）
绕过方法：设置上传路径为 upload/phpinfo.php%00 ,添加 phpinfo.php%00 内 容为了控制路径，上传文件后缀为白名单即可 例:test.jpg，保存后为 /upload/phpinfo.php%00test.jpg，但服务端读取到%00 时会自动结束，将文件 内容保存至 phpinfo.php 中
http://127.0.0.1/upload-labs-master/upload/pass12.php%EF%BF%BD/6720220305165151.jpg
http://127.0.0.1/upload-labs-master/upload/pass12.php
pass13(白名单 POST 型 0x00 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！";
}
}提交方式为POST
GET会自动解码
空格 ---->url 编码 %00
%00 ---->url 编码 %00
POST不会自动解码
%00 ---->url 编码 %25%30%30
因为 POST 不会像 GET 那样对%00 进行自动解码，
需要手动对进行编码
或者在 16 进制中修改
http://127.0.0.1/uploadlabsmaster/upload/pass13.php%EF%BF%BD/9120220305171015.jpg
http://127.0.0.1/upload-labs-master/upload/pass13.php
