Full Disclosure mailing list archives

Re: Google / GMail bug, all accounts vulnerable


From: "Andrew A" <gluttony () gmail com>
Date: Wed, 12 Dec 2007 12:36:16 -0800

PS-- Have you managed to get hired in an actual security position yet or are
you running around San Francisco begging for scraps from our tables?

PPS-- Namedropping the head of a project you plagiarized from in your cover
letter is not good policy. Especially in this industry. Its a smaller world
than most, and now you're blackballed buddy. You'll work as desktop support
at FOX forever. On this list you may act like the lack of credit was some
sort of forgetful slip, but most people have been relayed by now that you
directly claimed authorship of said shellcode in an interview.

Sucks to be you, I guess.

On Dec 12, 2007 12:01 PM, Andrew A <gluttony () gmail com> wrote:

Actually, the suggested prevention tactic is to create a post variable in
your form of type "hidden" with a securely generated one-time ticket that an
attacker would not be able to scrape without performing an xmlhttp call,
therefore signalling a (real) security problem with the app in question.
Requiring the user to re-input their login credentials for every database
write would be absolutely ridiculous from both a design and security
perspective.

But then again, you must know all this with your extensive experience in
web app security and development.


On Dec 12, 2007 9:31 AM, Kristian Erik Hermansen <kristian.hermansen () gmail com>
wrote:

On Dec 12, 2007 3:20 AM, ad () heapoverflow com <ad () heapoverflow com>
wrote:
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Hash: SHA1

ridiculous advisories are generating ridiculous replies that's well
known and you figured it out.

The data is all there.  So, the trick is how to utilize CSRF to
influence a large number of users to make requests which disrupt,
taint, or modify their accounts on popular services.  In the example,
I point the favicon.ico object as a 301 redirect to a GMail URI.
Since the favicon.ico object, for some reason, influences the account
even without revisiting the website again, the GMail account is again
influenced any time you click a tab.  It is an interesting finding,
and not one that I have heard ever publicly stated.  Correct me if I
am wrong here, but why would the favicon.ico object be requested every
time you merely click on a tab?  And does this only happen in FF, or
IE as well?   What other browser's exhibit this behavior and/or is it
supposed to be this way?

However, in addition to all this, CSRF is getting to be more
dangerous.  Major sites are not protecting against a wide range of
attacks.  The suggested prevention tactic is to ask for a password
upon any account modifications.  However, this does not always seem to
be implemented.  Too, many requests can cause distress to a user which
do not necessarily modify their accounts.  For instance, it is
possible to taint the credibility of a remote user as well.  Say you
could inject searches on Youtube for 'kiddie porn', or make Google
requests for 'how to murder your wife'.  All of these are possible
attacks, frightening, and how would they be prevented?  This is
becoming a large issue, and why I wrote up the PoC for the specific
Google / GMail case.  It is possible that these type of attacks could
perhaps be used to incriminate someone in court based on secondary
evidence, if they were suspected of say, murdering their wife.  The
user's search history on Google have been subpoenaed before, and
injecting requests into someone's search history is frightening and
definitely needs to be addressed, don't you think?  The worst part
about all of this is that there doesn't seem to be a viable solution
at the moment, which is why everyone should start thinking about the
problems now.  There are some great papers which describe a few
methods, but one demonstrating the implications is still missing...
--
Kristian Erik Hermansen
"I have no special talent. I am only passionately curious."

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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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