Is there any sort of "pre login" event or similar?

I need to run some code prior to checking if a user's credentials are correct. Currently I'm achieving this with a custom event listener that fires on the kernel.request event and checks if the requested URL matches security.yml's check_path setting. But this is inefficient since it runs on every request. I'm aware of the onSecurityInteractiveLogin event, but I believe that fires after a successful login attempt. Does anyone know if there's a pre login event, or where I could dispatch a custom event myself?