Description

The Vvveb admin panel allows authenticated administrators to modify plugin code without any validation, enabling the execution of arbitrary malicious code. This vulnerability is exploitable through the endpoint /vadmin123/index.php?module=editor/code&type=themes, where an admin can edit PHP files such as theme.php to inject and execute a reverse shell, granting unauthorized access to the web server.

Reproduce

1. Authenticate as an admin and navigate to the vulnerable endpoint:
   /vadmin123/index.php?module=editor/code&type=themes

2. Locate and edit the theme.php file. Replace its contents with the following PHP reverse shell payload (available here):
   Update the IP and port in the payload to match your listener (e.g., using Netcat).

3. Save the modified theme.php file.

4. Trigger execution by accessing:
   /vadmin123/index.php?module=editor/editor&url=/&template=index.html

5. Monitor your listener for the incoming connection. Example Netcat output:

   $ nc -lnvp 6060
   Listening on 0.0.0.0 6060
   Connection received on 127.0.0.1 33862
   Linux hx0 6.8.0-51-generic #52-Ubuntu SMP PREEMPT_DYNAMIC Thu Dec  5 13:09:44 UTC 2024 x86_64 Linux
   sh: w: not found
   uid=82(www-data) gid=82(www-data) groups=82(www-data),82(www-data)
   /bin/sh: can't access tty; job control turned off
   / $
   

Recommendation

• Implement Code Validation and Sanitization: Enforce server-side validation on all code uploads or edits in the admin panel, such as whitelisting allowed functions, scanning for dangerous patterns (e.g., exec(), system(), or network callbacks), or using a sandboxed execution environment.

• Restrict Admin Privileges: Limit file editing capabilities to trusted admins only, and use role-based access control (RBAC) to prevent broad code modification rights. Consider multi-factor authentication (MFA) for admin logins to mitigate brute-force risks.

• Secure File Handling: Disable direct PHP execution in theme/plugin directories by configuring the web server (e.g., via .htaccess rules or Nginx directives) to serve files as static content or parse them through a secure preprocessor. Regularly audit and hash uploaded files for integrity.

• General Best Practices: Keep Vvveb and all dependencies updated, conduct regular security audits, and monitor for anomalous admin activity. If chaining with XSS is a concern, implement Content Security Policy (CSP) headers and secure cookie attributes (e.g., HttpOnly and Secure).