Recently, as in the last two days, when I am in the process of filling in forms online, Firefox auto-fill offers me the choice of my phone number and a phone number that is unknown to me. I am 100% certain that I never erroneously entered this second number when filling in a previous form. The number bears no resemblance to my own. How the number came to be in Firefox auto-fill is a mystery to me. I used Canada 411 reverse look-up to check the number and discovered that it is a valid phone number belonging to a person I do not know and have never had any contact with. My question, then, is how did his phone number end up in Firefox on my computer? Is it possible I have been hacked?