Re: [Full-disclosure] silly PoCs continue: X-Frame-Options give you less than expected



Michal,

Interesting stuff indeed. However, I don't see you talk about a solution.

Why is that?

It seems Mr 65 here knows something about it seeing that he's complaining
about Firefox not having taken any measures (as if anyone is taking them
seriously when it comes to security...).

Anyhow, correct me if I'm wrong, but this concept won't work when the
attacked
site requires multiple user interaction, right? As in, the user will notice
something
amiss the second time.
In terms of usefulness, I don't see it practical unless the target doesn't
really employ good security practices, in which case, it would probably
already be vulnerable to plain XSRF...

Cheers,
Chris.


On Sat, Dec 10, 2011 at 11:39 PM, Michal Zalewski <lcamtuf@xxxxxxxxxxx>wrote:

At the risk of annoying everyone...

I think we greatly underappreciate the extent to which JavaScript
allows you to exploit the limits of human perception. On modern
high-performance systems, windows can be opened, positioned, and
closed; and documents loaded and then navigated away from; so quickly
that we can't even reliably notice that, let alone react consciously.

The PoC I posted here earlier this week
(http://lcamtuf.coredump.cx/switch/) demonstrates one example of page
transitions occurring so fast that you don't register it; and some of
my earlier posts outlined the exploitation of page switching to
exploit browser UIs (e.g. http://lcamtuf.coredump.cx/ffgeo2/). Today,
I wanted to share this brief demonstration of an attack that should
hopefully illustrate why our current way of thinking about
clickjacking (and the possible defenses, such as X-Frame-Options) is
flawed:

http://lcamtuf.coredump.cx/clickit/

The basic idea here is that instead of placing the UI you want to
tamper with in an invisible or only partly-visible <iframe>, you can
achieve a similar effect simply by predicting the time of a
premeditated click (which is fairly easy if you look at mouse velocity
and distance to the expected destination), and then either destroying
the current window, or navigating to a different document (in this
case, a cheesy banking site).

While everything about this exploit is extremely goofy, and I put no
effort into making the transitions less obvious, it should still
demonstrate the issue neatly.

/mz

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_______________________________________________
Full-Disclosure - We believe in it.
Charter: http://lists.grok.org.uk/full-disclosure-charter.html
Hosted and sponsored by Secunia - http://secunia.com/

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