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Re: Fwd: Google vulnerabilities with PoC
From: Chris Thompson <christhom7851 () gmail com>
Date: Fri, 14 Mar 2014 16:16:58 -0400

Hi Nicholas,

Again, you hypothesize that you are getting a response from the database,
but you really don't know that. You have no idea when the code is doing
behind the endpoint.

upload.youtube.com is simple an endpoint that you are sending a request to
and getting a response from -

Can you upload a ZIP file for example and then get that same ZIP file from
another machine? If you can do that, then who can question your bug.

Again, i'm not trying to be a dick - just trying to help!

Cheers...



On Fri, Mar 14, 2014 at 4:08 PM, Nicholas Lemonias. <
lem.nikolas () googlemail com> wrote:

My claim is now verified....

Cheers!


On Fri, Mar 14, 2014 at 8:04 PM, Nicholas Lemonias. <
lem.nikolas () googlemail com> wrote:

http://upload.youtube.com/?authuser=0&upload_id=
AEnB2UqVZlaog3GremriQEGDoUK3cdGGPu9MVIfyObgYajjo6i1--
uQicn6jhbwsdNrqSF4ApbUbhCcwzdwe4xf_XTbL_t5-aw&origin=
CiNodHRwOi8vd3d3LnlvdXR1YmUuY29tL3VwbG9hZC9ydXBpbxINdmlkZW8tdXBsb2Fkcw

That information can be queried from the db, where the metadata are
saved. The files are being saved persistently , as per the above example.


On Fri, Mar 14, 2014 at 8:04 PM, Nicholas Lemonias. <
lem.nikolas () googlemail com> wrote:


http://upload.youtube.com/?authuser=0&upload_id=AEnB2UqVZlaog3GremriQEGDoUK3cdGGPu9MVIfyObgYajjo6i1--uQicn6jhbwsdNrqSF4ApbUbhCcwzdwe4xf_XTbL_t5-aw&origin=CiNodHRwOi8vd3d3LnlvdXR1YmUuY29tL3VwbG9hZC9ydXBpbxINdmlkZW8tdXBsb2Fkcw

That information can be queried from the db, where the metadata are
saved. The files are being saved persistently , as per the above example.


On Fri, Mar 14, 2014 at 8:00 PM, Chris Thompson <christhom7851 () gmail com
wrote:

Hi Nikolas,

Please do read (and understand) my entire email before responding - I
understand your frustration trying to get your message across but maybe
this will help.

Please put aside professional pride for the time being - I know how it
feels to be passionate about something yet have others simply not
understand.

Let me try and bring some sanity to the discussion and explain to you
why people maybe not agreeing with you.

You (rightly so) highlighted what you believe to be an issue in a
Youtube whereby it appears (to you) than you can upload an arbitrary file.
If you can indeed do this as you suspect then your points are valid and you
"may" be able to cause various issues associated with it such as DOS etc -
especially if the uploaded files cannot or are not tracked.

However...

Consider than you are talking to an API and what you are getting back
(the JSON response) in your example is simply a response from the API to
say the file you uploaded has been received and saved.

Now, as you no doubt know, when you upload a regular movie to YouTube,
once uploaded it goes away and does some post-processing, converting it to
flash for example. What's to say that there isn't some verification aspect
to this post-processing that checks if the file is intact a valid movie and
if not removes it.

If you could for example demonstrate that the file was indeed
persistent, by being able to retrieve it for example then again, you would
have solid ground to claim an issue however your claims at this point are
based on an assumption.... Let me explain.

1. You have demonstrated than you can send "any" file to an API and the
API returned an acknowledgment of receiving (and saving) the file.

2. You / we don't know what Google do with files once they have been
received from the API - maybe they process them and validate them - we
simply don't know.

3. You have hypothesized that you can retrieve the file by manipulating
tokens etc and you may be right, but you have not demonstrated it as such.

Because of this, you seem to have made a CLAIM that you can upload
arbitrary files to Google however SHOWN that you can simply send files to
an API and an API responds in a certain way.

I am NOT saying you haven't found an issue, what I am saying is that
you need to demonstrate that the issue is real and thus can be abused. If
the Google service simply verifies all uploaded files once they are
uploaded and discards them if invalid, then you haven't really found
anything.

If you were to prove that you were able to retrieve this uploaded file
then how could anyone dispute your bug.

Hope this helps....

Cheers!





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