Here is the irony in your search. You are looking for a "Pro" license key, but the company that makes the software (now known as Xcitium, though they still use the Comodo brand) offers a completely free version that is superior to the 2012 Pro edition.

Comodo Free Internet Security (2025 version) includes:

You do not need a license key for the free version. You simply download it from the official Comodo website, install it, and it works forever.

When you search for "Comodo Internet Security Pro 2012 license key work," you are entering one of the most toxic corners of the internet. Websites offering free license keys, keygens, or cracks almost always have malicious intentions. Here is what actually happens when you try to "activate" old software illegally:

Some sites list "working keys." Even if one works, Comodo’s licensing servers have long since blacklisted those volume license keys. Worse, the website itself frequently uses malvertising—fake download buttons that install browser hijackers or adware.