Re: Chrome and Safari users open to stealth HTML5 Application Cache attack

[Chris Evans <scarybeasts () gmail com>]

Hello Lava,

It's an interesting twist but it does not seem to offer network
attackers any additional advantage beyond what they can already
achieve.

For example, a similar attack works against the Firefox and Opera
browsers I have installed on my laptop:

echo -ne 'HTTP/1.1 200 OK\r\nContent-Type:
text/html\r\nContent-Length: 28\r\nExpires: Sat, 01 Jan 2011 00:00:00
GMT\r\n\r\n<script>alert("hi")</script>' | nc -l -p 8080

In both instances, you can prime the cache for the root resource with
this payload. If you then completely restart the browsers, you'll see
that localhost:8080/ will still execute the script without even
consulting the network.

(Caching headers are browser and version sensitive so you may have to
fiddle with Max-Age, Cache-Control etc. depending on what you have).

In terms of your documented attack, the fake login page (step 6) is
shown over plain HTTP, i.e. the SSL lock icon will be missing. This
would be the same user experience as if the user were under attack via
SSLstrip.

In summary, any http hit on an insecure network is dangerous on all browsers.
(FWIW, Chromium resolves this for me. When I type mail<enter> into the
omnibar, it auto-completes to https://mail.google.com/)


Cheers
Chris

On Sun, Jun 27, 2010 at 3:28 PM, Lavakumar Kuppan <lava () andlabs org> wrote:
> Google Chrome and Safari support HTML5 Application Cache.
> But unlike Firefox and Opera they do not ask for user permission before
> allowing a site to create an Application Cache.
> On unsecured networks, attackers could stealthily
> create malicious Application Caches in the browser of victims for even HTTPS
> sites.
> It has always been possible to poison the browser cache and compromise the
> victim's account for HTTP based sites.
> With HTML5 Application Cache, it is possible to poison the cache of even
> HTTPS sites.
> Details
> - http://blog.andlabs.org/2010/06/chrome-and-safari-users-open-to-stealth.html
> I have also released a POC using which both Facebook and Gmail can be
> compromised.
> POC - http://www.andlabs.org/tools/imposter/imposter_poc.zip
> Video - http://www.youtube.com/watch?v=00sKMMyXJsI
>
> Cheers,
> Lava
> http://www.andlabs.org
>
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