文件上传漏洞——upload-labs(1-10)

其他 2020-03-24 22:11:47 阅读次数: 0

前言：文件上传漏洞有很多种绕过技巧，这次就通过upload-labs进行学习

第一关
在这里插入图片描述
上传有限制，只让上传JPEG或PNG格式的图片，就先尝试一下抓包修改上传格式的方法看看是否可行

先将一句话木马PHP文件后缀名改为PNG格式，上传拦截抓包

在这里插入图片描述
拦截请求包后，将1.png改为1.php，再发包，用菜刀进行连接，在此之前需要知道上传的文件上传到哪个目录下，查看源码查出图片上传路径
在这里插入图片描述
路径也知道了，就用菜刀进行连接
在这里插入图片描述
连接成功
在这里插入图片描述
观察一下第一关的源码

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;
    }
}

通过观察只是限制了在上传时的类型，所以中途拦截抓包改格式的方法是完成可行的。

方法：改包绕过上传

第二关
做第二关时发现沿用第一关的方法也是可行的，不过应该不会再考同一个点了

就查看一下源码

$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！';
    }
}

发现这一段代码判断content-type,那就可以通过修改content-type进行绕过：

  if (($_FILES['upload_file']['type'] == 'image/jpeg') || ($_FILES['upload_file']['type'] == 'image/png') || ($_FILES['upload_file']['type'] == 'image/gif'))

抓包将application/octet-stream修改为image/png或image/gif都可以在这里插入图片描述
连接成功
在这里插入图片描述
方法：修改content-type进行绕过

第三关

上传PHP文件时，发现有这样的提示
在这里插入图片描述
应该是源码中限制了这些文件的后缀名，查看大师傅们的博客发现还可以用

phtml，php3，php4, php5, pht

这些后缀名进行绕过，就来尝试一下，发现连接不上去，查了一下才知道原来前提是apache的httpd.conf中有如下配置代码

AddType application/x-httpd-php .php .phtml .phps .php5 .pht

在这里插入图片描述
我这里使用的是phpstudy+windows，即使添加了也不管用，查了大师傅的博客才知道是由于配置原因是解析不了php5等等这些后缀的，所以复现不了，可以在虚拟机中复现这关。
不过也知道了这一关是采用拓展名绕过
查看一下源码

$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']);//trim() 函数移除字符串两侧的空白字符或其他预定义字符
        $file_name = deldot($file_name);//删除文件名末尾的点
        $file_ext = strrchr($file_name, '.');//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。
        $file_ext = strtolower($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)) {//in_array() 函数搜索数组中是否存在指定的值
            $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！';
    }
}

观察源码就会发现这里确实采用黑名单来限制

方法：拓展名绕过

第四关
没什么思路，查看一下提示
在这里插入图片描述
发现基本上将所有非法的脚本后缀都禁用了，还是黑名单限制，查看一下源码

$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'];
            $img_path = UPLOAD_PATH.'/'.$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！';
    }
}

果然是将所有非法的脚本后缀都禁用了，但是没有禁用.htaccess，先来了解一下htaccess文件的作用，.htaccess的基本作用及相关语法介绍

在这里使用htaccess文件目的是为了将所有文件都当成php文件来解析
创建一个.htaccess文件

SetHandler application/x-httpd-php

在文件中写入该段代码，上传时将文件名去掉，只要后缀名
在这里插入图片描述
上传后，上传图片马，由于连接菜刀麻烦，这里就修改一句话语句为

<?php phpinfo(); ?>

上传图片马成功后，进行查看
在这里插入图片描述
解析成功

方法：.htaccess文件进行绕过

第五关

上传.htaccess文件，发现该后缀名也被加入黑名单了
在这里插入图片描述
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, '.');
        $file_ext = str_ireplace('::$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！';
    }
}

通过观察，发现黑名单中限制的后缀名没有将大小写统一，采用大小写方式进行绕过
在这里插入图片描述
在这里插入图片描述
上传成功，进行查看
在这里插入图片描述

方法：大小写绕过

第六关

无论如果改后缀名都无法上传，说明这关代码已经统一了大小写
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 = $_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！';
    }
}

还是采用了黑名单来进行限制，不过与前几关先比较会发现少了这一行代码

$file_ext = trim($file_ext); //首尾去空

那么就可以采用后缀名中加空绕过
在这里插入图片描述
在后缀名中加入空格.php空格，再发包，上传成功
在这里插入图片描述

方法：后缀名加空绕过

第七关

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']);
        $file_ext = strrchr($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！';
    }
}

还是黑名单，这次又有什么不一样的，通过与前几关对比发现少了这行代码

 $file_name = deldot($file_name);//删除文件名末尾的点

所以可以采用后缀名加.的方式绕过，在这之前，先来了解一下对Windows系统文件命名规则的特殊利用

	shell.php.                    ———-文件名后加点‘.’

   shell.php(空格)               ———-文件名后加括号空格

   shell.php:1.jpg               ———-文件名后加冒号’:’

   shell.php::$DATA             ———-文件名后加NTFS ADS特性::$DATA

   shell.php::$DATA……           ———-文件名后::$DATA……

会被windows系统自动去掉不符合规则符号后面的内容。

windows系统文件命名规则的特殊利用

因此我们可以先抓包然后在后缀名后加上.，文件上传时由于不符合windows文件命名规则而将.去掉，从而将.php的文件上传进去

在这里插入图片描述
访问
在这里插入图片描述
绕过方法：后缀名加.绕过

第八关
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
        $file_ext = trim($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！';
    }
}

还是黑名单限制，观察一下与之前有那些不同

发现少了这一段代码

$file_ext = str_ireplace('::$DATA', '', $file_ext);//去除字符串::$DATA

没有去除字符串::$DATA，根据Windows系统文件命名规则进行抓包修改即可

shell.php::$DATA             ———-文件名后加NTFS ADS特性::$DATA

原理和第七关类似
在这里插入图片描述
访问成功
在这里插入图片描述
绕过方法：后缀名加::$DATA绕过

第九关

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！';
    }
}

观察看与前几关的代码有什么不同的地方，发现

$img_path = UPLOAD_PATH.'/'.$file_name;

路径拼接的是处理后的文件名$file_name，而不是$file_ext，也就是说最后保存文件的时候没有重命名而使用的原始的文件名，那相当于$file_name只经过那两段代码的过滤

$file_name = trim($_FILES['upload_file']['name']);//移除字符串两侧的空白字符
$file_name = deldot($file_name);//删除文件名末尾的点

那就可以采用**后缀名（点+空格+点）**的方法来绕过
在这里插入图片描述
上传时，代码会先将末尾的.去除，剩余.+空格，利用Windows系统文件命名规则，windows会忽略文件末尾的.和空格，这样即可上传进取

在这里插入图片描述

绕过方法：后缀名+.+空格+.进行绕过

第十关

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","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);
        $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！';
    }
}
#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。*/

这一段代码将后缀名全部替换成了空

$file_name = str_ireplace($deny_ext,"", $file_name);

之前学习XSS时也碰到这种情况，可以采用双写进行绕过
在这里插入图片描述
过滤了php，前后再拼接成PHP
访问成功：
在这里插入图片描述

绕过方法：双写绕过

总结：通过这十关又学到了很多文件上传的技巧，下次继续学习后十关，这次先学习到这里。

~Lemon
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