Sites Leaking Users' Email Addresses

Pisang writes "CNet is running a story about how spammers and phishers can learn about our surfing habits to better target their attacks. According to the article, web sites that use e-mail addresses as IDs are vulnerable to attacks that could leak their users' email addresses. These attacks are performed by requesting a password reminder for an address or trying to register with it."

Comments

Re:Another problem

[idonthack]

Well, if you let your e-mail address expire, and someone else registers it later on, they won't have trouble doing a password request which will allow them into your account, which will contain your personal information.

This is the reason that most ISPs and web mail providers don't allow anybody to register an email that's been registered at any time in the past.

Re:Add your pros and cons here

[argent]

cons for using email as login

Here's another one, and it ties into the original posting: it's the same problem as using biometrics for identification: using an ID or password that's hard to change. You don't want to use that kind of ID casually, because you want to make sure that people who have your ID have an incentive to be at least as careful with it as you would be.

If you use your thumbprint to pay for a drink at a bar, how good a job do you think the bar is going to do about making sure someone else doesn't game their sensor with a bit of latex on their fingertip? If someone steals your credit card, you can cancel it and get a new credit card. If someone steals your thumbprint you're hosed.

This is the same kind of thing. If someone finds out that there's someone with the handle "fishdan" on slashdot, they don't have anything useful. If they have your email address, they have something useful that's hard to change (look at me, I'm using year-tagged email addresses and I'm thinking of going to month tags). Plus, if you DO change your email address you have to change it EVERYWHERE (which is why I've got spam filters that reject entire countries for my main email address... because I've had it for about as long as personal domains have been available and I'm really loath to dump it).

And because of all this, what this means is that all email addresses have to be treated as disposable, even the supposedly private ones you use for account registration only. Which means that now your email address has the same problem as any other name: you have to remember a bunch of them, you have to remember where you used them, and if you only keep 'em long enough for the verification you can't relogin with the old address.

Don't PATCH it, FIX it.

[argent]

Maybe this security issue could be solved by instead of sticking up a message saying "email not found" if the email is entered incorrectly, it could randomly generate the "secret questions".

I've got a better idea. Don't require the user to give you their email address EXCEPT for initial registration. Don't use their email address as their ID. Don't ask for email address for password reset*. Just take the user ID, send the message, and have done with it.

This is a case where there's really no good and easy way to fix the security problem except by backing up and not doing the thing that causes the problem. This is like someone's saying "I want to leave my front door open while I'm not at home, so my cat can get in and out." and then coming up with "Well, you can set up a webcam to close the door when something bigger than a car comes up" instead of "Don't DO that, use a cat-flap".

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* Why sites do that, I don't know... there's no extra security from having a login name AND and email address typed in by the user, since the verification mail won't go to anyone but the real user... all it does for me is make me generate a new account 'cos I don't know what email address I used to sign up with because of exactly this kind of problem.