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Browser auto-fill phishing

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Re: Browser auto-fill phishing

#123
post #90

Earlier quoted context omitted.

This requires the browser to recognize it as a credit card field. Suppose a form uses a non-standard name for the field (say a localized name), and a user enters it at a legitimate site. Any attacker simply has to find these non-standard names for auto-complete to fill this in. I feel like I've seen a credit card autofill before outside of normal controls.

But then the browser won't autofill it, so what's the problem?

It will if the attacker uses the same custom name for his field. The attacker could try to suck as much data as possible by creating thousands of hidden fields having a lot of possible combinations for the names of these non-standard CC fields, and wait to get lucky.

Re: Browser auto-fill phishing

#124
post #38

Earlier quoted context omitted.

> If an element isn't drawn it shouldn't be autofilled. So if a form is too long and you need to scroll, all those fields you can't see won't be auto-filled? Sounds pretty terrible IMO.

Well why not have it autofill on-draw?

It'd be easy to move the hidden elements on to the screen when the user clicks the submit button, so they'd be filled in and the form would then be submitted, and the information 'phished'.

The solution to this problem is to inform the user which fields will be completed by autofill, with a "not currently shown" highlight on any fields that are currently off the screen so the user understands what's happening.

Re: Browser auto-fill phishing

#125

This could be solved by improving the autofill UI to tell you all the data it is filling into the form, even if it isn't visible to you. Currently, when I trigger autofill in Chrome, it tells me the full suite of information it can input for a certain profile (name, address, company, etc), but it doesn't tell me which bits of information are actually being used. Something as simple as placing checkmarks in this popup…

> This could be solved by improving the autofill UI to tell you all the data it is filling into the form, even if it isn't visible to you.

Safari does this already

Re: Browser auto-fill phishing

#126
post #25

I'd rather have only the field I selected autofilled and be given a secondary option to have every field (or maybe choose which fields) in a form autofilled. This bothers me in innocent, non-phishing forms too—especially when the designers don't put labels on the fields and only use placeholders, which I can no longer see after autofill.

Safari lets you choose which fields to fill in by clicking a "Customize" option that pops up, but I doubt any normal user will bother looking that far.

Re: Browser auto-fill phishing

#127
post #7

Earlier quoted context omitted.

The elements are not hidden, they are just drawn off the screen. So the browser would have to determine if the item is visible to the user, which is not trivial. Should autofill skip regular form elements that are just a little below the viewport? Maybe some feedback from the browser detailing which datapoints were autofilled. I don't know...

Another method would be to show a user a list of all fields that are about to be filled in as part of the autocomplete prompt. This isn't very scalable for massive forms, but should be enough of an alert to a user that something is amiss on screen to make up for those cases.

Safari does this already

Re: Browser auto-fill phishing

#128
post #65
post #7

Earlier quoted context omitted.

The elements are not hidden, they are just drawn off the screen. So the browser would have to determine if the item is visible to the user, which is not trivial. Should autofill skip regular form elements that are just a little below the viewport? Maybe some feedback from the browser detailing which datapoints were autofilled. I don't know...

My thinking is the user should explicitly autofill each field. Yes, it involves more work, but it's really not much work to click on a field and pick the right autofill value. I'm always concerned about using autofill because browsers eagerly fill any field they have data for.

Firefox works that way and is in my view a much saner default. The best solution used to be in Opera long ago where they showed a little dropdown with the information that was going to be autofilled. You could accept it or deny it.

Re: Browser auto-fill phishing

#129
post #10

Firefox doesn't exhibit this behavior, but the site doesn't specifically state which browsers this affects.

Firefox is secure against this. FF needs you to right click an input field and select an identity to use for autofill.

But Safari does it in the most elegant way. They show a popup with all the information that will be autofilled and ask you to confirm before filling out the fields which also protects against AJAXified submissions.

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