CVE-2024-21762 Check – Identifying Vulnerability In FortiGate SSL VPNs

It provides a detailed guide on how to check if a FortiGate SSL VPN is vulnerable to CVE-2024-21762, a critical security flaw. Utilizing a Python script, users can quickly determine whether their VPN is at risk.

The process, outlined with clear usage instructions, is designed for IT professionals and system administrators to ensure their network’s security against potential exploits.

Safely detect whether a FortiGate SSL VPN is vulnerable to CVE-2024-21762. For more information, see this Bishop Fox blog post

Usage

python3 check-cve-2024-21762.py <host> <port>

In most cases, the script will either output “Vulnerable” or “Patched”.

It performs minimal verification that the target is in fact a FortiOS SSL VPN, and in some cases it will print a warning before providing output.

If this happens, double check that your target is a FortiOS SSL VPN interface and not a management interface.

# Testing against the SSL-VPN interface
$ python3 check-cve-2024-21762.py 192.168.250.124 12443
Vulnerable

# Testing against the management interface -> bogus results
$ python3 check-cve-2024-21762.py 192.168.250.124 443
[warning] Server does not look like a Fortinet SSL VPN interface
Patched