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New Firefox iFrame Bug Bypasses URL Protections
Trailrunner7 writes "There is a newly discovered vulnerability in Mozilla's flagship Firefox browser that could enable an attacker to trick a user into providing his login credentials for a given site by using an obfuscated URL. In most cases, Firefox will display an alert when a URL has been obfuscated, but by using an iFrame, an attacker can evade this layer of protection, possibly leading to a compromise of the user's sensitive information."
If you rely on some alert or some fancy feature for protection, you really aren't being as proactive as you could. Regardless of what any alerts might or might not say, if the URL doesn't look right, err on the side of caution. While there are always exceptions, if you don't know what a "good" URL looks like, take the time to educate yourself.
My mom always said, "Jim, you're 1 in a million." Given the current population, there are 7000 of me. God help us all!
You can update the status bar to indicate something else, you can use the legitimate site as a username for a non-legitimate site (i.e. www.google.com@www.malwaresite.com), or you can just make the URL look as official as possible (i.e. ebay-secure.com) and hope people believe it's authentic.
You can also access the site numerically (e.g. http://1208929379/ is Google) but that's more for fun than evil.
They say a little knowledge is a dangerous thing, but it's not one half so bad as a lot of ignorance. - Terry Pratchett
It's not even a security issue as far as I'm concerned. It's just one of their bonus services not detecting bad sites properly. There is no vulnerability in the browser itself, it's the user.
The blog post that TFA refers to should be this one:
http://blog.armorize.com/2010/08/iframes-and-url-stringency-mozilla.html
(Yea, their typing skills don't impress me either.)
That in turn links to a BugZilla entry, though it's locked down at the moment.
I work for Mozilla on Firefox and I just wanted to respond to some of the claims being made here. We've opened up the bug so that others can take a look (bug 570658), but there is not much to see, here. The bug says that:
1) if you visit a page that uses an iframe
2) and that iframe's src attribute uses a deceptive url (e.g. "http://safe.com@evil.com")
3) then we don't pop up a warning that the url is deceptive
What's odd about the bug is that there is very little value to step 2 - only someone examining the page's source would notice the iframe's src attribute, so it's not clear to me where the deception is supposed to come in. A genuinely malicious page would source their attack iframes directly, unless they thought that this deceptive url might fool our phishing/malware protection. It won't.
If someone thinks we're overlooking an attack vector here, we're really interested to hear it, but as described the attack feels pretty weak.
If you think we're missing something critical, please do comment in the bug or get in touch with our security group ( http://www.mozilla.org/security/ ).
Johnathan