Message-ID: <CA+CewVBQNPTT8Vpfag4GqGo5SRAcTH7m82TCD8f3rcqxAWaoBg@mail.gmail.com>
Date: Fri, 14 Mar 2014 19:33:23 +0000
From: "Nicholas Lemonias." <lem.nikolas@...glemail.com>
To: Julius Kivimäki <julius.kivimaki@...il.com>, 
 full-disclosure@...ts.grok.org.uk
Subject: Re: Fwd: Google vulnerabilities with PoC

It is an example, citing that there has been a security hole on Youtube
that needs patching. End of Story.


On Fri, Mar 14, 2014 at 7:32 PM, Julius Kivimäki
<julius.kivimaki@...il.com>wrote:

> Wait, so "remote code execution by social engineering" wasn't a troll? I'm
> confused.
>
>
> 2014-03-14 21:28 GMT+02:00 Nicholas Lemonias. <lem.nikolas@...glemail.com>
> :
>
> Then that also means that firewalls and IPS systems are worthless. Why
>> spend so much time protecting the network layers if a user can send any
>> file of choice to a remote network through http...
>>
>> As for the uploaded files being persistent, there is evidence of that.
>> For instance a remote admin could be tricked to execute some of
>> the uploaded files (Social Engineering).
>>
>> So our report sent as part of Google's security program, should not be
>> treated as a non-security issue.
>>
>>
>> Thanks,
>>
>>
>> On Fri, Mar 14, 2014 at 7:23 PM, R D <rd.seclists@...il.com> wrote:
>>
>>> I'm going to try to spell it out clearly.
>>>
>>> You don't have unrestricted file upload[1]. Keep in mind you're trying
>>> to abuse youtube, which is essentially a video file upload service. So the
>>> fact that you can upload files is not surprising.
>>> Now you're uploading non-video files. Cool. But not earth-shattering.
>>> They are not accessible to anyone but you, as far as I can tell, and I
>>> don't even think you can access the file contents on the remote server, but
>>> please prove me wrong on both points.
>>> You are still, as far as I can tell, bound by the per-file and
>>> per-account quota on disk occupation, so you don't have a DoS by resource
>>> exhaustion.
>>> You can't force server-side file path, so you don't have RFI or DoS by
>>> messing with the remote file system. You can't execute the files you
>>> uploaded, so you don't have arbitrary code execution.
>>>
>>> But you are right about what your PoC does. You bypassed a security
>>> control, you uploaded crap on youtube servers, and by that you exhausted
>>> their resources by a fraction of the quota they allow you when signing up.
>>> BTW, I don't think they keep invalid video files for an indefinite period
>>> of time in a user account, but I might be wrong.
>>>
>>> The burden of proof is still on your side as to whether or not the bug
>>> you found has any impact that was not already accepted by youtube allowing
>>> registered users to upload whatever crap they see fit as long as it is
>>> video. You failed to provide this proof, and please be sure the audience of
>>> fulldisclosure is not "attacking the researcher" but working with you to
>>> have a better understanding of the bug you found, even though you kinda
>>> acted like a fool in this thread.
>>>
>>> Please keep on searching and finding vulns, please keep on publishing
>>> them, and use this as a learning experience that not all bugs or control
>>> bypasses are security vulnerabilities.
>>>
>>> --Rob'
>>>
>>> [1] As per OWASP (
>>> https://www.owasp.org/index.php/Unrestricted_File_Upload):
>>>
>>> >There are really two classes of problems here. The first is with the
>>> file metadata, like the path and file name. These are generally provided by
>>> the transport, such as HTTP multi-part encoding. This data may trick the
>>> application into overwriting a critical file or storing the file in a bad
>>> location. You must validate the metadata extremely carefully before using
>>> it.
>>>
>>> Your POC doesn't demonstrate that.
>>>
>>> >The other class of problem is with the file size or content. The range
>>> of problems here depends entirely on what the file is used for. See the
>>> examples below for some ideas about how files might be misused. To protect
>>> against this type of attack, you should analyze everything your application
>>> does with files and think carefully about what processing and interpreters
>>> are involved.
>>>
>>> Your POC kinda does that, but you didn't provide proof it's possible to
>>> execute what you uploaded, either using social engineering or any other
>>> method.
>>>
>>> Also, please don't say "verified by a couple of recognised experts
>>> including OWASP" unless you actually spoke with someone @owasp and she
>>> validated your findings.
>>>
>>>
>>> On Fri, Mar 14, 2014 at 7:40 PM, Nicholas Lemonias. <
>>> lem.nikolas@...glemail.com> wrote:
>>>
>>>> We have many PoC's including video clips. We may upload for the
>>>> security world to see.
>>>>
>>>> However, this is not the way to treat security vulnerabilities.
>>>> Attacking the researcher and bringing you friends to do aswell, won't
>>>> mitigate the problem.
>>>>
>>>>
>>>>
>>>> _______________________________________________
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>>>>
>>>
>>>
>>
>> _______________________________________________
>> Full-Disclosure - We believe in it.
>> Charter: http://lists.grok.org.uk/full-disclosure-charter.html
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>>
>
>

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