I guess I'm discovering this really late, but apparently many modems have default passwords that are all the same for a given model, and that includes admin passwords! What's more, you can get a list of the modem and their passwords on the internet!! And most people don't bother changing the password!!! I'm running out of exclamation marks!!!!

http://securityspread.com/2013/07/01/modem-secure/

Whose bright idea is this? I can understand if a modem comes with default passwords specific to that individual modem, but for all modems of the same model to have the same passwords...

So, boys and girls, change your modem passwords (including the admin password) if you haven't ever done so.