Other usernames (not my own) showing up in login fields online (non-shared computer)

[sarahsugar]

First off, I apologize in advance if I posted this in the wrong board, but it didn't seem to fit in the other ones.

Specs: I use Windows XP Professional, Service Pack 2 and my browser is Firefox 3.0.13

For the past few weeks I've been noticing every now and then that when I go to login somewhere online, other people's usernames will show up in the drop down box in the Username field. For example, if I'd logged into a few different myspace accounts with different e-mail addresses, when I clicked the Username field while logging in it might list the various e-mails I've used to log in recently...well that's been happening, except with other people's usernames and accounts. The password hasn't filled in automatically any of the times, but these strange usernames will be listed there and it's making me wonder what the cause of this is and if its potentially dangerous.

There's no possibility of someone having logged in to any sites on this computer other than myself since I live alone and my computer is password protected...I'm the only one who's ever used this computer to my knowledge.

So what could this be? These usernames do not ring a bell to me at all, and after googling them, the ones that do show up (most of them don't) will belong to people from across the country who I've never heard of. Could I have been hacked? Or have a virus? Or have had my identity stolen or my computer taken over by somebody else? Or is this just a common fluke or something? I'm not sure how paranoid I should be in this situation, but since I log in to things like my bank account with this computer it makes me nervous seeing these other usernames appear in the login fields.

Another thing I should mention is that I have it set so that it automatically clears my cookies/private data whenever I exit Firefox...I also have Norton 360 installed and it's detected nothing out of the ordinary, even after multiple full scans.

Thanks in advance for any help!!

 

[fw2004]

Are all of the other user names listed similar to yours? In other words, is this like the browser's auto-fill feature, where it starts to recognize what you are typing, and fills in the rest?

Do you use Norton Identity Safe?
That's just a curiosity.

How do you access the Internet?
Are you on a wireless connection, and if so, do you have encryption enabled?

If you leave your computer on while you're away, and the computer is always connected to the Internet, I suppose it is possible that someone has planted a trojan into your machine and is using your computer as a gateway to access web sites to which this user does not want to leave traces of his activity.

What sort of environment do you live in?
Apartment, rented home, or do you own the place?

If it's rented, I guess there is always the possibility that someone could be getting in with a key during the day and accessing your computer.

But even if someone were to be accessing your computer, you did say that it is password protected, so this user would not be able to log onto your account and leave traces of his activity in your browser (even if he is using your computer under a different user).

Are you up to date on your Norton 360?

Do you have any special file sharing (like peer to peer) programs installed?

Do you have the Windows Guest account turned on?

If there is a possibility that someone is accessing your computer while you're out, try setting the BIOS password.
That will add one more layer of security to what Windows already provides.

This is very interesting. I would like to help you, and know what you eventually find.

On the lighter side; is it possible that you are accessing your computer in your sleep, or while under the influence of some medication?
I know that Ambien (a med to help you sleep) will do strange things to me. I have written stuff (locally) while taking it that I did not recognize later when I read it.

FW